{"id":302,"date":"2024-10-23T11:05:38","date_gmt":"2024-10-23T02:05:38","guid":{"rendered":"https:\/\/dexall.co.jp\/articles\/?p=302"},"modified":"2025-03-24T08:53:25","modified_gmt":"2025-03-23T23:53:25","slug":"java-hashmap%e3%83%9e%e3%82%b9%e3%82%bf%e3%83%bc%e8%ac%9b%e5%ba%a7%ef%bc%9a%e5%9f%ba%e7%a4%8e%e3%81%8b%e3%82%89%e5%bf%9c%e7%94%a8%e3%81%be%e3%81%a7%e5%ae%8c%e5%85%a8%e8%a7%a3%e8%aa%ac%e3%80%90","status":"publish","type":"post","link":"https:\/\/dexall.co.jp\/articles\/?p=302","title":{"rendered":"Java HashMap\u30de\u30b9\u30bf\u30fc\u8b1b\u5ea7\uff1a\u57fa\u790e\u304b\u3089\u5fdc\u7528\u307e\u3067\u5b8c\u5168\u89e3\u8aac\u3010\u73fe\u5f79\u30a8\u30f3\u30b8\u30cb\u30a2\u76f4\u4f1d\u3011"},"content":{"rendered":"<div id=\"sgb-css-id-1\">\n<p>\u3042\u306a\u305f\u306f\u65e5\u3005\u306eJava\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u3067\u3001\u30c7\u30fc\u30bf\u3092\u52b9\u7387\u7684\u306b\u7ba1\u7406\u3057\u3001\u9ad8\u901f\u306b\u30a2\u30af\u30bb\u30b9\u3059\u308b\u65b9\u6cd5\u3092\u63a2\u3057\u3066\u3044\u307e\u305b\u3093\u304b\uff1f\u305d\u3093\u306a\u3042\u306a\u305f\u306b\u3001Java\u306eHashMap\u3092\u30de\u30b9\u30bf\u30fc\u3059\u308b\u6c7a\u5b9a\u7248\u306e\u8a18\u4e8b\u3092\u304a\u5c4a\u3051\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-2\">\n<p>HashMap\u306f\u3001Java\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u306b\u304a\u3051\u308b\u6700\u3082\u5f37\u529b\u3067\u6c4e\u7528\u6027\u306e\u9ad8\u3044\u30c7\u30fc\u30bf\u69cb\u9020\u306e\u4e00\u3064\u3067\u3059\u3002\u30ad\u30fc\u3068\u5024\u306e\u30da\u30a2\u3067\u30c7\u30fc\u30bf\u3092\u7ba1\u7406\u3059\u308b\u3053\u306e\u9023\u60f3\u914d\u5217\u306f\u3001\u305d\u306e\u9ad8\u901f\u306a\u691c\u7d22\u6027\u80fd\u3068\u67d4\u8edf\u306a\u4f7f\u7528\u65b9\u6cd5\u304b\u3089\u3001\u591a\u304f\u306e\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3084\u30d5\u30ec\u30fc\u30e0\u30ef\u30fc\u30af\u3067\u5e83\u304f\u63a1\u7528\u3055\u308c\u3066\u3044\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-3\">\n<div class=\"toc\"><br \/>\n<b>Warning<\/b>:  Undefined array key \"is_admin\" in <b>\/home\/xs392991\/dexall.co.jp\/public_html\/articles\/wp-content\/themes\/sango-theme\/library\/gutenberg\/dist\/classes\/Toc.php<\/b> on line <b>116<\/b><br \/>\n<br \/>\n<b>Warning<\/b>:  Undefined array key \"is_category_top\" in <b>\/home\/xs392991\/dexall.co.jp\/public_html\/articles\/wp-content\/themes\/sango-theme\/library\/gutenberg\/dist\/classes\/Toc.php<\/b> on line <b>121<\/b><br \/>\n<br \/>\n<b>Warning<\/b>:  Undefined array key \"is_top\" in <b>\/home\/xs392991\/dexall.co.jp\/public_html\/articles\/wp-content\/themes\/sango-theme\/library\/gutenberg\/dist\/classes\/Toc.php<\/b> on line <b>128<\/b><br \/>\n    <div id=\"toc_container\" class=\"sgb-toc--bullets js-smooth-scroll\" data-dialog-title=\"\u76ee\u6b21\">\n      <p class=\"toc_title\">\u76ee\u6b21 <\/p>\n      <ul class=\"toc_list\">  <li class=\"first\">    <a href=\"#i-0\">\u306a\u305cHashMap\u3092\u30de\u30b9\u30bf\u30fc\u3059\u308b\u5fc5\u8981\u304c\u3042\u308b\u306e\u304b\uff1f<\/a>  <\/li>  <li>    <a href=\"#i-1\">1. HashMap\u3068\u306f\uff1f\u57fa\u672c\u6982\u5ff5\u3068\u7279\u5fb4\u3092\u5fb9\u5e95\u89e3\u8aac<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-2\">1.1 \u30ad\u30fc\u3068\u5024\u306e\u30da\u30a2\u3067\u7ba1\u7406\u3059\u308bHashMap\u306e\u57fa\u672c<\/a>      <\/li>      <li>        <a href=\"#i-3\">1.2 HashMap\u304c\u9078\u3070\u308c\u308b\u7406\u7531\uff1a\u9ad8\u901f\u306a\u691c\u7d22\u3068\u67d4\u8edf\u306a\u4f7f\u7528<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-8\">\u5b9f\u969b\u306e\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u30b7\u30ca\u30ea\u30aa\u3067\u306e\u6d3b\u7528\u4f8b<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-9\">2. HashMap\u306e\u4e3b\u8981\u30e1\u30bd\u30c3\u30c9\u3068\u57fa\u672c\u64cd\u4f5c<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-10\">2.1 put()\u3068get()\uff1a\u30c7\u30fc\u30bf\u306e\u8ffd\u52a0\u3068\u53d6\u5f97\u306e\u57fa\u672c<\/a>      <\/li>      <li>        <a href=\"#i-13\">2.2 remove()\u3068clear()\uff1a\u52b9\u7387\u7684\u306a\u30c7\u30fc\u30bf\u524a\u9664\u30c6\u30af\u30cb\u30c3\u30af<\/a>      <\/li>      <li>        <a href=\"#i-16\">2.3 containsKey()\u3068containsValue()\uff1a\u5b58\u5728\u78ba\u8a8d\u306e\u88cf\u6280<\/a>      <\/li>      <li>        <a href=\"#i-19\">\u305d\u306e\u4ed6\u306e\u6709\u7528\u306a\u30e1\u30bd\u30c3\u30c9<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-20\">\u30e1\u30bd\u30c3\u30c9\u306e\u7d44\u307f\u5408\u308f\u305b\u306b\u3088\u308b\u4e00\u822c\u7684\u306a\u64cd\u4f5c\u30d1\u30bf\u30fc\u30f3<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-24\">3. HashMap\u306e\u5185\u90e8\u69cb\u9020\u3068\u52d5\u4f5c\u539f\u7406<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-25\">3.1 \u30cf\u30c3\u30b7\u30e5\u30c6\u30fc\u30d6\u30eb\u306e\u4ed5\u7d44\u307f\uff1a\u9ad8\u901f\u30a2\u30af\u30bb\u30b9\u306e\u79d8\u5bc6<\/a>      <\/li>      <li>        <a href=\"#i-26\">3.2 LoadFactor\u3068Rehash\uff1a\u81ea\u52d5\u7684\u306a\u6027\u80fd\u6700\u9069\u5316<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-28\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3078\u306e\u5f71\u97ff<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-29\">4. HashMap\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u30c1\u30e5\u30fc\u30cb\u30f3\u30b0<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-30\">4.1 \u521d\u671f\u5bb9\u91cf\u306e\u9069\u5207\u306a\u8a2d\u5b9a\uff1a\u30e1\u30e2\u30ea\u52b9\u7387\u3092\u9ad8\u3081\u308b<\/a>      <\/li>      <li>        <a href=\"#i-31\">4.2 \u30ab\u30b9\u30bf\u30e0\u30ad\u30fc\u306e\u5229\u7528\uff1ahashCode()\u3068equals()\u306e\u30aa\u30fc\u30d0\u30fc\u30e9\u30a4\u30c9<\/a>      <\/li>      <li>        <a href=\"#i-32\">HashMap\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u306b\u5f71\u97ff\u3092\u4e0e\u3048\u308b\u8981\u56e0<\/a>      <\/li>      <li>        <a href=\"#i-33\">\u52b9\u7387\u7684\u306a\u30ad\u30fc\u9078\u629e<\/a>      <\/li>      <li>        <a href=\"#i-34\">\u30d0\u30b1\u30c3\u30c8\u306e\u5206\u5e03\u5206\u6790<\/a>      <\/li>      <li>        <a href=\"#i-35\">Java 8\u4ee5\u964d\u306e\u6700\u9069\u5316\u6a5f\u80fd\u306e\u6d3b\u7528<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-36\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u30c1\u30e5\u30fc\u30cb\u30f3\u30b0\u306e\u52b9\u679c\u6e2c\u5b9a<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-37\">5. HashMap\u3068\u4ed6\u306eMap\u5b9f\u88c5\u306e\u6bd4\u8f03<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-38\">5.1 HashMap\u3068TreeMap\uff1a\u9806\u5e8f\u4ed8\u3051\u306e\u9055\u3044\u3068\u4f7f\u3044\u5206\u3051<\/a>      <\/li>      <li>        <a href=\"#i-39\">5.2 HashMap\u3068LinkedHashMap\uff1a\u633f\u5165\u9806\u5e8f\u306e\u7dad\u6301\u304c\u5fc5\u8981\u306a\u5834\u5408<\/a>      <\/li>      <li>        <a href=\"#i-40\">\u6027\u80fd\u6bd4\u8f03<\/a>      <\/li>      <li>        <a href=\"#i-41\">\u305d\u306e\u4ed6\u306e\u91cd\u8981\u306aMap\u5b9f\u88c5<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-42\">\u9069\u5207\u306aMap\u5b9f\u88c5\u306e\u9078\u629e\u6307\u91dd<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-43\">6. HashMap\u306e\u5b9f\u8df5\u7684\u306a\u4f7f\u7528\u4f8b\u3068\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-44\">6.1 \u983b\u51fa\u30d1\u30bf\u30fc\u30f3\uff1a\u30b0\u30eb\u30fc\u30d4\u30f3\u30b0\u3068\u30ab\u30a6\u30f3\u30c6\u30a3\u30f3\u30b0<\/a>      <\/li>      <li>        <a href=\"#i-47\">6.2 \u4e26\u5217\u51e6\u7406\u3067\u306e\u6ce8\u610f\u70b9\uff1aConcurrentHashMap\u306e\u6d3b\u7528<\/a>      <\/li>      <li>        <a href=\"#i-48\">HashMap\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/a>      <\/li>      <li>        <a href=\"#i-49\">\u4e00\u822c\u7684\u306a\u843d\u3068\u3057\u7a74\u3068\u56de\u907f\u65b9\u6cd5<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-50\">\u5b9f\u969b\u306e\u30d7\u30ed\u30b8\u30a7\u30af\u30c8\u3067\u306e\u4f7f\u7528\u4f8b<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-51\">7. Java 8\u4ee5\u964d\u306eHashMap\uff1a\u65b0\u6a5f\u80fd\u3068\u6539\u5584\u70b9<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-52\">7.1 computeIfAbsent()\u3068merge()\uff1a\u6761\u4ef6\u4ed8\u304d\u64cd\u4f5c\u306e\u7c21\u7565\u5316<\/a>      <\/li>      <li>        <a href=\"#i-55\">7.2 forEach()\u3068replaceAll()\uff1a\u30e9\u30e0\u30c0\u5f0f\u3092\u6d3b\u7528\u3057\u305f\u52b9\u7387\u7684\u306a\u51e6\u7406<\/a>      <\/li>      <li>        <a href=\"#i-58\">\u5185\u90e8\u5b9f\u88c5\u306e\u6539\u5584<\/a>      <\/li>      <li>        <a href=\"#i-59\">Java 9\u4ee5\u964d\u306e\u8ffd\u52a0\u6539\u5584\u70b9<\/a>      <\/li>      <li>        <a href=\"#i-60\">\u65b0\u6a5f\u80fd\u6d3b\u7528\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-61\">\u307e\u3068\u3081<\/a>      <\/li>    <\/ul>  <\/li>  <li class=\"last\">    <a href=\"#i-62\">8. HashMap\u3092\u30de\u30b9\u30bf\u30fc\u3059\u308b\u305f\u3081\u306e\u6b21\u306e\u30b9\u30c6\u30c3\u30d7<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-63\">8.1 \u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6e2c\u5b9a\uff1a\u81ea\u4f5c\u306e\u30d9\u30f3\u30c1\u30de\u30fc\u30af\u30c6\u30b9\u30c8<\/a>      <\/li>      <li>        <a href=\"#i-64\">8.2 \u5b9f\u52d9\u3067\u306e\u6d3b\u7528\uff1a\u30ea\u30a2\u30eb\u30ef\u30fc\u30eb\u30c9\u306e\u4f7f\u7528\u4f8b\u3068\u6ce8\u610f\u70b9<\/a>      <\/li>      <li>        <a href=\"#i-65\">\u6b21\u306e\u30b9\u30c6\u30c3\u30d7\uff1a\u3055\u3089\u306a\u308b\u5b66\u7fd2\u3068\u63a2\u6c42<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-66\">\u307e\u3068\u3081<\/a>      <\/li>    <\/ul>  <\/li><\/ul>\n      <a href=\"#\" class=\"sgb-toc-button js-toc-button\" rel=\"nofollow\" data-open-dialog=\"true\"><i class=\"fa fa-list\"><\/i><span class=\"sgb-toc-button__text\">\u76ee\u6b21\u3078<\/span><\/a>\n    <\/div><\/div><h2 class=\"wp-block-heading\" id=\"i-0\">\u306a\u305cHashMap\u3092\u30de\u30b9\u30bf\u30fc\u3059\u308b\u5fc5\u8981\u304c\u3042\u308b\u306e\u304b\uff1f<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-6\">\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">HashMap\u306e\u7279\u5fb4<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ol class=\"wp-block-list\"><div id=\"sgb-css-id-4\">\n<li><strong>\u9a5a\u7570\u7684\u306a\u691c\u7d22\u901f\u5ea6<\/strong>\uff1a HashMap\u306e\u5e73\u5747\u691c\u7d22\u6642\u9593\u8907\u96d1\u5ea6\u306fO(1)\u3067\u3059\u3002\u3064\u307e\u308a\u3001\u30c7\u30fc\u30bf\u91cf\u306b\u95a2\u4fc2\u306a\u304f\u3001\u307b\u307c\u4e00\u5b9a\u306e\u6642\u9593\u3067\u76ee\u7684\u306e\u30c7\u30fc\u30bf\u306b\u30a2\u30af\u30bb\u30b9\u3067\u304d\u307e\u3059\u3002<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-5\">\n<li><strong>\u5e45\u5e83\u3044\u5fdc\u7528\u6027<\/strong>\uff1a \u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u306e\u30ad\u30e3\u30c3\u30b7\u30e5\u304b\u3089\u3001\u30b0\u30e9\u30d5\u30a2\u30eb\u30b4\u30ea\u30ba\u30e0\u306e\u5b9f\u88c5\u307e\u3067\u3001HashMap\u306e\u4f7f\u7528\u7bc4\u56f2\u306f\u591a\u5c90\u306b\u308f\u305f\u308a\u307e\u3059\u3002<\/li>\n<\/div>\n\n\n<li><strong>\u7d99\u7d9a\u7684\u306a\u9032\u5316<\/strong>\uff1a Java 8\u4ee5\u964d\u3001HashMap\u306e\u5185\u90e8\u5b9f\u88c5\u304c\u6539\u5584\u3055\u308c\u3001\u3055\u3089\u306a\u308b\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u5411\u4e0a\u304c\u5b9f\u73fe\u3057\u3066\u3044\u307e\u3059\u3002\u6700\u65b0\u306e\u6a5f\u80fd\u3092\u7406\u89e3\u3059\u308b\u3053\u3068\u3067\u3001\u3088\u308a\u52b9\u7387\u7684\u306a\u30b3\u30fc\u30c9\u304c\u66f8\u3051\u308b\u3088\u3046\u306b\u306a\u308a\u307e\u3059\u3002<\/li>\n<\/ol>\n<\/div><\/div>\n<\/div>\n\n\n<p>\u672c\u8a18\u4e8b\u3067\u306f\u3001HashMap\u306e\u57fa\u790e\u304b\u3089\u5fdc\u7528\u307e\u3067\u3001\u73fe\u5f79\u30a8\u30f3\u30b8\u30cb\u30a2\u306e\u8996\u70b9\u304b\u3089\u5fb9\u5e95\u7684\u306b\u89e3\u8aac\u3057\u307e\u3059\u3002\u521d\u5fc3\u8005\u306e\u65b9\u304b\u3089\u3001\u3059\u3067\u306bHashMap\u3092\u4f7f\u7528\u3057\u3066\u3044\u308b\u4e2d\u7d1a\u8005\u3001\u3055\u3089\u306b\u306f\u30b7\u30b9\u30c6\u30e0\u8a2d\u8a08\u3084\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316\u306b\u643a\u308f\u308b\u4e0a\u7d1a\u8005\u307e\u3067\u3001\u5168\u3066\u306eJava\u30a8\u30f3\u30b8\u30cb\u30a2\u306b\u4fa1\u5024\u3042\u308b\u60c5\u5831\u3092\u304a\u5c4a\u3051\u3057\u307e\u3059\u3002<\/p>\n\n\n<div id=\"sgb-css-id-7\">\n<p>\u4ee5\u4e0b\u306e\u30c8\u30d4\u30c3\u30af\u3092\u901a\u3058\u3066\u3001\u3042\u306a\u305f\u306eHashMap\u6d3b\u7528\u30b9\u30ad\u30eb\u3092\u6b21\u306e\u30ec\u30d9\u30eb\u3078\u3068\u5f15\u304d\u4e0a\u3052\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-14\">\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">\u672c\u8a18\u4e8b\u3067\u5b66\u3079\u308b\u3053\u3068<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ul class=\"wp-block-list\"><div id=\"sgb-css-id-8\">\n<li>HashMap\u306e\u57fa\u672c\u6982\u5ff5\u3068\u7279\u5fb4<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-9\">\n<li>\u4e3b\u8981\u30e1\u30bd\u30c3\u30c9\u3068\u57fa\u672c\u64cd\u4f5c\u306e\u8a73\u7d30<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-10\">\n<li>\u5185\u90e8\u69cb\u9020\u3068\u52d5\u4f5c\u539f\u7406\u306e\u89e3\u660e<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-11\">\n<li>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u30c1\u30e5\u30fc\u30cb\u30f3\u30b0\u306e\u79d8\u8a23<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-12\">\n<li>\u4ed6\u306eMap\u5b9f\u88c5\u3068\u306e\u6bd4\u8f03<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-13\">\n<li>\u5b9f\u8df5\u7684\u306a\u4f7f\u7528\u4f8b\u3068\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/li>\n<\/div>\n\n\n<li>Java 8\u4ee5\u964d\u306e\u65b0\u6a5f\u80fd\u3068\u6539\u5584\u70b9<\/li>\n<\/ul>\n<\/div><\/div>\n<\/div>\n\n<div id=\"sgb-css-id-15\">\n<p>\u3055\u3042\u3001Java\u306eHashMap\u30de\u30b9\u30bf\u30fc\u3078\u306e\u9053\u3092\u4e00\u7dd2\u306b\u6b69\u307f\u307e\u3057\u3087\u3046\u3002\u3053\u306e\u8a18\u4e8b\u3092\u8aad\u307f\u7d42\u308f\u308b\u9803\u306b\u306f\u3001HashMap\u3092\u81ea\u4fe1\u3092\u6301\u3063\u3066\u4f7f\u3044\u3053\u306a\u3057\u3001\u3088\u308a\u52b9\u7387\u7684\u3067\u6d17\u7df4\u3055\u308c\u305fJava\u30b3\u30fc\u30c9\u3092\u66f8\u3051\u308b\u3088\u3046\u306b\u306a\u3063\u3066\u3044\u308b\u306f\u305a\u3067\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-16\">\n<h2 class=\"wp-block-heading\" id=\"i-1\">1. HashMap\u3068\u306f\uff1f\u57fa\u672c\u6982\u5ff5\u3068\u7279\u5fb4\u3092\u5fb9\u5e95\u89e3\u8aac<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-17\">\n<p>HashMap\u306f\u3001Java\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u306b\u304a\u3044\u3066\u6975\u3081\u3066\u91cd\u8981\u306a\u30c7\u30fc\u30bf\u69cb\u9020\u306e\u4e00\u3064\u3067\u3059\u3002\u305d\u306e\u57fa\u672c\u6982\u5ff5\u3068\u7279\u5fb4\u3092\u7406\u89e3\u3059\u308b\u3053\u3068\u306f\u3001\u52b9\u7387\u7684\u306a\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u306e\u7b2c\u4e00\u6b69\u3068\u306a\u308a\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-18\">\n<h3 class=\"wp-block-heading\" id=\"i-2\">1.1 \u30ad\u30fc\u3068\u5024\u306e\u30da\u30a2\u3067\u7ba1\u7406\u3059\u308bHashMap\u306e\u57fa\u672c<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-19\">\n<p>HashMap\u306f\u3001\u30ad\u30fc\u3068\u5024\u306e\u30da\u30a2\u3067\u30c7\u30fc\u30bf\u3092\u683c\u7d0d\u3059\u308b\u9023\u60f3\u914d\u5217\u306e\u4e00\u7a2e\u3067\u3059\u3002java.util\u30d1\u30c3\u30b1\u30fc\u30b8\u306b\u542b\u307e\u308c\u3001Map\u30a4\u30f3\u30bf\u30fc\u30d5\u30a7\u30fc\u30b9\u3092\u5b9f\u88c5\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">\u30ad\u30fc\u3068\u5024\u306e\u30da\u30a2\u306e\u6982\u5ff5<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ul class=\"wp-block-list\"><div id=\"sgb-css-id-20\">\n<li><strong>\u30ad\u30fc<\/strong>\uff1a \u30c7\u30fc\u30bf\u3092\u8b58\u5225\u3059\u308b\u305f\u3081\u306e\u4e00\u610f\u306e\u8b58\u5225\u5b50<\/li>\n<\/div>\n\n\n<li><strong>\u5024<\/strong>\uff1a \u30ad\u30fc\u306b\u95a2\u9023\u4ed8\u3051\u3089\u308c\u305f\u5b9f\u969b\u306e\u30c7\u30fc\u30bf<\/li>\n<\/ul>\n<\/div><\/div>\n\n\n<div id=\"sgb-css-id-21\">\n<p>\u4f8b\u3048\u3070\u3001\u5f93\u696d\u54e1\u7ba1\u7406\u30b7\u30b9\u30c6\u30e0\u3067HashMap\u3092\u4f7f\u7528\u3059\u308b\u5834\u5408\u3001\u6b21\u306e\u3088\u3046\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">HashMap&lt;String, Employee&gt; employeeMap = new HashMap&lt;&gt;();\nemployeeMap.put(\"E001\", new Employee(\"John Doe\", \"IT Department\"));\nemployeeMap.put(\"E002\", new Employee(\"Jane Smith\", \"HR Department\"));\n\n\/\/ \u5f93\u696d\u54e1\u60c5\u5831\u306e\u53d6\u5f97\nEmployee employee = employeeMap.get(\"E001\");\nSystem.out.println(employee.getName()); \/\/ \u51fa\u529b: John Doe<\/pre>\n\n\n<div id=\"sgb-css-id-22\">\n<p>\u3053\u306e\u30b3\u30fc\u30c9\u4f8b\u3067\u306f\u3001\u5f93\u696d\u54e1ID\uff08\u30ad\u30fc\uff09\u3092\u4f7f\u3063\u3066\u5f93\u696d\u54e1\u60c5\u5831\uff08\u5024\uff09\u3092\u683c\u7d0d\u3057\u3001\u53d6\u5f97\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-26\">\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">HashMap\u306e\u4e3b\u8981\u306a\u7279\u5fb4<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ol class=\"wp-block-list\"><div id=\"sgb-css-id-23\">\n<li><strong>\u30cc\u30eb\u8a31\u5bb9<\/strong>\uff1a \u30ad\u30fc\u3068\u5024\u306e\u4e21\u65b9\u306bnull\u3092\u4f7f\u7528\u3067\u304d\u307e\u3059\u3002<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-24\">\n<li><strong>\u975e\u540c\u671f<\/strong>\uff1a \u30c7\u30d5\u30a9\u30eb\u30c8\u3067\u306fthread-safe\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-25\">\n<li><strong>\u9806\u5e8f\u4e0d\u4fdd\u6301<\/strong>\uff1a \u8981\u7d20\u306e\u633f\u5165\u9806\u5e8f\u3092\u4fdd\u6301\u3057\u307e\u305b\u3093\u3002<\/li>\n<\/div>\n\n\n<li><strong>\u91cd\u8907\u30ad\u30fc\u4e0d\u53ef<\/strong>\uff1a \u540c\u3058\u30ad\u30fc\u3067\u65b0\u3057\u3044\u5024\u3092\u8ffd\u52a0\u3059\u308b\u3068\u3001\u53e4\u3044\u5024\u304c\u4e0a\u66f8\u304d\u3055\u308c\u307e\u3059\u3002<\/li>\n<\/ol>\n<\/div><\/div>\n<\/div>\n\n<div id=\"sgb-css-id-27\">\n<h3 class=\"wp-block-heading\" id=\"i-3\">1.2 HashMap\u304c\u9078\u3070\u308c\u308b\u7406\u7531\uff1a\u9ad8\u901f\u306a\u691c\u7d22\u3068\u67d4\u8edf\u306a\u4f7f\u7528<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-28\">\n<p>HashMap\u304c\u591a\u304f\u306e\u5834\u9762\u3067\u9078\u3070\u308c\u308b\u7406\u7531\u306f\u3001\u305d\u306e\u9ad8\u901f\u306a\u691c\u7d22\u6027\u80fd\u3068\u4f7f\u3044\u3084\u3059\u3055\u306b\u3042\u308a\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-29\">\n<h4 class=\"wp-block-heading\" id=\"i-4\">\u9ad8\u901f\u306a\u691c\u7d22\u6027\u80fd<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-30\">\n<p>HashMap\u306e\u5e73\u5747\u691c\u7d22\u6642\u9593\u8907\u96d1\u5ea6\u306fO(1)\u3067\u3059\u3002\u3053\u308c\u306f\u3001\u30c7\u30fc\u30bf\u91cf\u306b\u95a2\u308f\u3089\u305a\u3001\u307b\u307c\u4e00\u5b9a\u306e\u6642\u9593\u3067\u76ee\u7684\u306e\u30c7\u30fc\u30bf\u306b\u30a2\u30af\u30bb\u30b9\u3067\u304d\u308b\u3053\u3068\u3092\u610f\u5473\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-31\">\n<h4 class=\"wp-block-heading\" id=\"i-5\">\u67d4\u8edf\u306a\u4f7f\u7528<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-32\">\n<p>\u30b8\u30a7\u30cd\u30ea\u30af\u30b9\u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u69d8\u3005\u306a\u578b\u306e\u30ad\u30fc\u3068\u5024\u3092\u6271\u3048\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">HashMap&lt;Integer, String&gt; numberWords = new HashMap&lt;&gt;();\nHashMap&lt;String, List&lt;String&gt;&gt; categoryItems = new HashMap&lt;&gt;();\nHashMap&lt;CustomObject, AnotherCustomObject&gt; complexMap = new HashMap&lt;&gt;();<\/pre>\n\n\n<div id=\"sgb-css-id-33\">\n<h4 class=\"wp-block-heading\" id=\"i-6\">\u30e1\u30e2\u30ea\u52b9\u7387<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-34\">\n<p>\u9069\u5207\u306b\u4f7f\u7528\u3059\u308c\u3070\u3001HashMap\u306f\u6bd4\u8f03\u7684\u30e1\u30e2\u30ea\u52b9\u7387\u304c\u826f\u3044\u30c7\u30fc\u30bf\u69cb\u9020\u3067\u3059\u3002\u305f\u3060\u3057\u3001\u521d\u671f\u5bb9\u91cf\u3068\u30ed\u30fc\u30c9\u30d5\u30a1\u30af\u30bf\u30fc\u306e\u8a2d\u5b9a\u306b\u6ce8\u610f\u304c\u5fc5\u8981\u3067\u3059\uff08\u3053\u308c\u306b\u3064\u3044\u3066\u306f\u5f8c\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u8a73\u3057\u304f\u8aac\u660e\u3057\u307e\u3059\uff09\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-35\">\n<h4 class=\"wp-block-heading\" id=\"i-7\">HashMap\u306e\u5229\u70b9\u3068\u6b20\u70b9<\/h4>\n<\/div>\n\n<div id=\"id-e664ed02-ec2d-4134-af48-182a0b42ebe3\"><div id=\"sgb-css-id-36\">\n<figure class=\"wp-block-table\"><table><thead><tr><th>\u5229\u70b9<\/th><th>\u6b20\u70b9<\/th><\/tr><\/thead><tbody><tr><td>\u9ad8\u901f\u306a\u691c\u7d22\u3068\u633f\u5165<\/td><td>\u9806\u5e8f\u3092\u4fdd\u6301\u3057\u306a\u3044<\/td><\/tr><tr><td>\u4f7f\u3044\u3084\u3059\u3044 API<\/td><td>\u540c\u671f\u3055\u308c\u3066\u3044\u306a\u3044\uff08\u30de\u30eb\u30c1\u30b9\u30ec\u30c3\u30c9\u74b0\u5883\u3067\u306e\u4f7f\u7528\u306b\u6ce8\u610f\u304c\u5fc5\u8981\uff09<\/td><\/tr><tr><td>\u67d4\u8edf\u306a\u30ad\u30fc\u3068\u5024\u306e\u578b<\/td><td>\u30ad\u30fc\u306e\u30cf\u30c3\u30b7\u30e5\u30b3\u30fc\u30c9\u306e\u8cea\u306b\u6027\u80fd\u304c\u4f9d\u5b58\u3059\u308b<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div><\/div>\n\n\n<h3 class=\"wp-block-heading\" id=\"i-8\">\u5b9f\u969b\u306e\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u30b7\u30ca\u30ea\u30aa\u3067\u306e\u6d3b\u7528\u4f8b<\/h3>\n\n\n<div id=\"sgb-css-id-39\">\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">\u5b9f\u969b\u306e\u6d3b\u7528\u4f8b<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ol class=\"wp-block-list\"><div id=\"sgb-css-id-37\">\n<li><strong>\u30ad\u30e3\u30c3\u30b7\u30e5\u306e\u5b9f\u88c5<\/strong>\uff1a \u983b\u7e41\u306b\u30a2\u30af\u30bb\u30b9\u3059\u308b\u30c7\u30fc\u30bf\u3092\u9ad8\u901f\u306b\u53d6\u5f97<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-38\">\n<li><strong>\u30b0\u30e9\u30d5\u3084\u30c4\u30ea\u30fc\u306e\u8868\u73fe<\/strong>\uff1a \u30ce\u30fc\u30c9\u9593\u306e\u95a2\u4fc2\u3092\u52b9\u7387\u7684\u306b\u7ba1\u7406<\/li>\n<\/div>\n\n\n<li><strong>\u983b\u5ea6\u30ab\u30a6\u30f3\u30c8<\/strong>\uff1a \u6587\u5b57\u3084\u5358\u8a9e\u306e\u51fa\u73fe\u56de\u6570\u3092\u8ffd\u8de1<\/li>\n<\/ol>\n<\/div><\/div>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/\/ \u5358\u8a9e\u306e\u51fa\u73fe\u56de\u6570\u3092\u30ab\u30a6\u30f3\u30c8\u3059\u308b\u4f8b\nHashMap&lt;String, Integer&gt; wordCount = new HashMap&lt;&gt;();\nString text = \"Java HashMap is efficient Java HashMap is fast\";\nfor (String word : text.split(\" \")) {\n    wordCount.put(word, wordCount.getOrDefault(word, 0) + 1);\n}\nSystem.out.println(wordCount); \/\/ \u51fa\u529b: {fast=1, efficient=1, is=2, Java=2, HashMap=2}<\/pre>\n\n\n<div id=\"sgb-css-id-40\">\n<p>HashMap\u306e\u57fa\u672c\u6982\u5ff5\u3068\u7279\u5fb4\u3092\u7406\u89e3\u3059\u308b\u3053\u3068\u3067\u3001\u3088\u308a\u52b9\u7387\u7684\u306a\u30c7\u30fc\u30bf\u7ba1\u7406\u304c\u53ef\u80fd\u306b\u306a\u308a\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001HashMap\u306e\u4e3b\u8981\u30e1\u30bd\u30c3\u30c9\u3068\u57fa\u672c\u64cd\u4f5c\u306b\u3064\u3044\u3066\u8a73\u3057\u304f\u898b\u3066\u3044\u304d\u307e\u3057\u3087\u3046\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-41\">\n<h2 class=\"wp-block-heading\" id=\"i-9\">2. HashMap\u306e\u4e3b\u8981\u30e1\u30bd\u30c3\u30c9\u3068\u57fa\u672c\u64cd\u4f5c<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-42\">\n<p>HashMap\u3092\u52b9\u679c\u7684\u306b\u4f7f\u7528\u3059\u308b\u305f\u3081\u306b\u306f\u3001\u305d\u306e\u4e3b\u8981\u30e1\u30bd\u30c3\u30c9\u3068\u57fa\u672c\u64cd\u4f5c\u3092\u7406\u89e3\u3059\u308b\u3053\u3068\u304c\u4e0d\u53ef\u6b20\u3067\u3059\u3002\u3053\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u6700\u3082\u983b\u7e41\u306b\u4f7f\u7528\u3055\u308c\u308b\u30e1\u30bd\u30c3\u30c9\u3068\u305d\u306e\u4f7f\u7528\u65b9\u6cd5\u306b\u3064\u3044\u3066\u8a73\u3057\u304f\u8aac\u660e\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-43\">\n<h3 class=\"wp-block-heading\" id=\"i-10\">2.1 put()\u3068get()\uff1a\u30c7\u30fc\u30bf\u306e\u8ffd\u52a0\u3068\u53d6\u5f97\u306e\u57fa\u672c<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-44\">\n<h4 class=\"wp-block-heading\" id=\"i-11\">put(K key, V value)<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-45\">\n<p><code>put()<\/code>\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u6307\u5b9a\u3055\u308c\u305f\u30ad\u30fc\u3068\u5024\u306e\u30de\u30c3\u30d4\u30f3\u30b0\u3092HashMap\u306b\u8ffd\u52a0\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">HashMap&lt;String, Integer&gt; scores = new HashMap&lt;&gt;();\nInteger previousScore = scores.put(\"Alice\", 95);\nSystem.out.println(\"Previous score: \" + previousScore); \/\/ \u51fa\u529b: Previous score: null\n\n\/\/ \u65e2\u5b58\u306e\u30ad\u30fc\u306b\u5bfe\u3057\u3066\u65b0\u3057\u3044\u5024\u3092\u8a2d\u5b9a\npreviousScore = scores.put(\"Alice\", 98);\nSystem.out.println(\"Previous score: \" + previousScore); \/\/ \u51fa\u529b: Previous score: 95<\/pre>\n\n\n\n<ul class=\"wp-block-list is-style-sango-list-simple\"><div id=\"sgb-css-id-46\">\n<li>\u623b\u308a\u5024\uff1a \u6307\u5b9a\u3055\u308c\u305f\u30ad\u30fc\u306b\u4ee5\u524d\u95a2\u9023\u4ed8\u3051\u3089\u308c\u3066\u3044\u305f\u5024\uff08\u5b58\u5728\u3057\u306a\u3044\u5834\u5408\u306fnull\uff09<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-47\">\n<li>\u6ce8\u610f\uff1a \u65e2\u5b58\u306e\u30ad\u30fc\u306b\u5bfe\u3057\u3066put()\u3092\u4f7f\u7528\u3059\u308b\u3068\u3001\u53e4\u3044\u5024\u304c\u65b0\u3057\u3044\u5024\u3067\u4e0a\u66f8\u304d\u3055\u308c\u307e\u3059<\/li>\n<\/div><\/ul>\n\n\n<div id=\"sgb-css-id-48\">\n<h4 class=\"wp-block-heading\" id=\"i-12\">get(Object key)<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-49\">\n<p><code>get()<\/code>\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u6307\u5b9a\u3055\u308c\u305f\u30ad\u30fc\u306b\u95a2\u9023\u4ed8\u3051\u3089\u308c\u305f\u5024\u3092\u53d6\u5f97\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">Integer aliceScore = scores.get(\"Alice\");\nSystem.out.println(\"Alice's score: \" + aliceScore); \/\/ \u51fa\u529b: Alice's score: 98\n\nInteger bobScore = scores.get(\"Bob\");\nSystem.out.println(\"Bob's score: \" + bobScore); \/\/ \u51fa\u529b: Bob's score: null<\/pre>\n\n\n\n<ul class=\"wp-block-list is-style-sango-list-simple\"><div id=\"sgb-css-id-50\">\n<li>\u623b\u308a\u5024\uff1a \u30ad\u30fc\u306b\u95a2\u9023\u4ed8\u3051\u3089\u308c\u305f\u5024\uff08\u5b58\u5728\u3057\u306a\u3044\u5834\u5408\u306fnull\uff09<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-51\">\n<li>\u6ce8\u610f\uff1a \u5b58\u5728\u3057\u306a\u3044\u30ad\u30fc\u306b\u5bfe\u3057\u3066get()\u3092\u4f7f\u7528\u3057\u3066\u3082\u30a8\u30e9\u30fc\u306f\u767a\u751f\u305b\u305a\u3001null\u304c\u8fd4\u3055\u308c\u307e\u3059<\/li>\n<\/div><\/ul>\n\n\n<div id=\"sgb-css-id-52\">\n<h3 class=\"wp-block-heading\" id=\"i-13\">2.2 remove()\u3068clear()\uff1a\u52b9\u7387\u7684\u306a\u30c7\u30fc\u30bf\u524a\u9664\u30c6\u30af\u30cb\u30c3\u30af<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-53\">\n<h4 class=\"wp-block-heading\" id=\"i-14\">remove(Object key)<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-54\">\n<p><code>remove()<\/code>\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u6307\u5b9a\u3055\u308c\u305f\u30ad\u30fc\u306e\u30de\u30c3\u30d4\u30f3\u30b0\u3092\u524a\u9664\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">Integer removedScore = scores.remove(\"Alice\");\nSystem.out.println(\"Removed score: \" + removedScore); \/\/ \u51fa\u529b: Removed score: 98\n\n\/\/ \u5b58\u5728\u3057\u306a\u3044\u30ad\u30fc\u306e\u524a\u9664\u3092\u8a66\u307f\u308b\nremovedScore = scores.remove(\"Charlie\");\nSystem.out.println(\"Removed score: \" + removedScore); \/\/ \u51fa\u529b: Removed score: null<\/pre>\n\n\n\n<ul class=\"wp-block-list is-style-sango-list-simple\"><div id=\"sgb-css-id-55\">\n<li>\u623b\u308a\u5024\uff1a \u524a\u9664\u3055\u308c\u305f\u5024\uff08\u30ad\u30fc\u304c\u5b58\u5728\u3057\u306a\u3044\u5834\u5408\u306fnull\uff09<\/li>\n<\/div><\/ul>\n\n\n<div id=\"sgb-css-id-56\">\n<h4 class=\"wp-block-heading\" id=\"i-15\">clear()<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-57\">\n<p><code>clear()<\/code>\u30e1\u30bd\u30c3\u30c9\u306f\u3001HashMap\u304b\u3089\u3059\u3079\u3066\u306e\u30de\u30c3\u30d4\u30f3\u30b0\u3092\u524a\u9664\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">scores.clear();\nSystem.out.println(\"Map size after clear: \" + scores.size()); \/\/ \u51fa\u529b: Map size after clear: 0<\/pre>\n\n\n\n<ul class=\"wp-block-list is-style-sango-list-simple\"><div id=\"sgb-css-id-58\">\n<li>\u6ce8\u610f\uff1a \u5927\u91cf\u306e\u8981\u7d20\u3092\u524a\u9664\u3059\u308b\u5834\u5408\u3001\u500b\u5225\u306b<code>remove()<\/code>\u3092\u547c\u3073\u51fa\u3059\u3088\u308a\u3082<code>clear()<\/code>\u3092\u4f7f\u7528\u3059\u308b\u65b9\u304c\u52b9\u7387\u7684\u3067\u3059<\/li>\n<\/div><\/ul>\n\n\n<div id=\"sgb-css-id-59\">\n<h3 class=\"wp-block-heading\" id=\"i-16\">2.3 containsKey()\u3068containsValue()\uff1a\u5b58\u5728\u78ba\u8a8d\u306e\u88cf\u6280<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-60\">\n<h4 class=\"wp-block-heading\" id=\"i-17\">containsKey(Object key)<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-61\">\n<p><code>containsKey()<\/code>\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u6307\u5b9a\u3055\u308c\u305f\u30ad\u30fc\u306e\u30de\u30c3\u30d4\u30f3\u30b0\u304c\u5b58\u5728\u3059\u308b\u304b\u3092\u78ba\u8a8d\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">boolean hasAlice = scores.containsKey(\"Alice\");\nSystem.out.println(\"Contains Alice: \" + hasAlice); \/\/ \u51fa\u529b: Contains Alice: false<\/pre>\n\n\n\n<ul class=\"wp-block-list is-style-sango-list-simple\"><div id=\"sgb-css-id-62\">\n<li>\u6027\u80fd\uff1a \u975e\u5e38\u306b\u9ad8\u901f\uff08\u5e73\u5747\u6642\u9593\u8907\u96d1\u5ea6O(1)\uff09<\/li>\n<\/div><\/ul>\n\n\n<div id=\"sgb-css-id-63\">\n<h4 class=\"wp-block-heading\" id=\"i-18\">containsValue(Object value)<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-64\">\n<p><code>containsValue()<\/code>\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u6307\u5b9a\u3055\u308c\u305f\u5024\u306b\u5bfe\u3059\u308b\u30de\u30c3\u30d4\u30f3\u30b0\u304c1\u3064\u4ee5\u4e0a\u5b58\u5728\u3059\u308b\u304b\u3092\u78ba\u8a8d\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">scores.put(\"Bob\", 85);\nscores.put(\"Charlie\", 85);\n\nboolean has85 = scores.containsValue(85);\nSystem.out.println(\"Contains score 85: \" + has85); \/\/ \u51fa\u529b: Contains score 85: true<\/pre>\n\n\n\n<ul class=\"wp-block-list is-style-sango-list-simple\"><div id=\"sgb-css-id-65\">\n<li>\u6027\u80fd\uff1a \u4f4e\u901f\uff08\u6642\u9593\u8907\u96d1\u5ea6O(n)\u3001\u5168\u8981\u7d20\u306e\u8d70\u67fb\u304c\u5fc5\u8981\uff09<\/li>\n<\/div><\/ul>\n\n\n<div id=\"sgb-css-id-66\">\n<h3 class=\"wp-block-heading\" id=\"i-19\">\u305d\u306e\u4ed6\u306e\u6709\u7528\u306a\u30e1\u30bd\u30c3\u30c9<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-69\">\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">\u305d\u306e\u4ed6\u306e\u6709\u7528\u306a\u30e1\u30bd\u30c3\u30c9<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ul class=\"wp-block-list\"><div id=\"sgb-css-id-67\">\n<li><code>size()<\/code>\uff1a \u30de\u30c3\u30d7\u5185\u306e\u30ad\u30fc\u3068\u5024\u306e\u30da\u30a2\u306e\u6570\u3092\u8fd4\u3057\u307e\u3059<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-68\">\n<li><code>isEmpty()<\/code>\uff1a \u30de\u30c3\u30d7\u304c\u7a7a\u304b\u3069\u3046\u304b\u3092\u78ba\u8a8d\u3057\u307e\u3059<\/li>\n<\/div>\n\n\n<li><code>putAll(Map&lt;? extends K, ? extends V&gt; m)<\/code>\uff1a \u6307\u5b9a\u3055\u308c\u305f\u30de\u30c3\u30d7\u306e\u3059\u3079\u3066\u306e\u30de\u30c3\u30d4\u30f3\u30b0\u3092\u3053\u306e\u30de\u30c3\u30d7\u306b\u30b3\u30d4\u30fc\u3057\u307e\u3059<\/li>\n<\/ul>\n<\/div><\/div>\n<\/div>\n\n<div id=\"sgb-css-id-70\">\n<h3 class=\"wp-block-heading\" id=\"i-20\">\u30e1\u30bd\u30c3\u30c9\u306e\u7d44\u307f\u5408\u308f\u305b\u306b\u3088\u308b\u4e00\u822c\u7684\u306a\u64cd\u4f5c\u30d1\u30bf\u30fc\u30f3<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-71\">\n<h4 class=\"wp-block-heading\" id=\"i-21\">\u30ad\u30fc\u306e\u5b58\u5728\u78ba\u8a8d\u5f8c\u306e\u64cd\u4f5c<\/h4>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">if (scores.containsKey(\"David\")) {\n    int davidScore = scores.get(\"David\");\n    \/\/ David\u306e\u30b9\u30b3\u30a2\u3092\u4f7f\u7528\u3057\u305f\u51e6\u7406\n} else {\n    \/\/ David\u304c\u5b58\u5728\u3057\u306a\u3044\u5834\u5408\u306e\u51e6\u7406\n}<\/pre>\n\n\n<div id=\"sgb-css-id-72\">\n<h4 class=\"wp-block-heading\" id=\"i-22\">\u6761\u4ef6\u4ed8\u304d\u8ffd\u52a0<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-73\">\n<p><code>putIfAbsent()<\/code>\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u7528\u3059\u308b\u3068\u3001\u30ad\u30fc\u304c\u5b58\u5728\u3057\u306a\u3044\u5834\u5408\u306b\u306e\u307f\u5024\u3092\u8ffd\u52a0\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">scores.putIfAbsent(\"Eve\", 90);\nSystem.out.println(\"Eve's score: \" + scores.get(\"Eve\")); \/\/ \u51fa\u529b: Eve's score: 90\n\n\/\/ \u65e2\u5b58\u306e\u30ad\u30fc\u306b\u5bfe\u3057\u3066putIfAbsent()\u3092\u4f7f\u7528\nscores.putIfAbsent(\"Eve\", 95);\nSystem.out.println(\"Eve's score after putIfAbsent: \" + scores.get(\"Eve\")); \/\/ \u51fa\u529b: Eve's score after putIfAbsent: 90<\/pre>\n\n\n<div id=\"sgb-css-id-74\">\n<h4 class=\"wp-block-heading\" id=\"i-23\">\u5024\u306e\u66f4\u65b0<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-75\">\n<p><code>replace()<\/code>\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u7528\u3059\u308b\u3068\u3001\u30ad\u30fc\u304c\u5b58\u5728\u3059\u308b\u5834\u5408\u306b\u306e\u307f\u5024\u3092\u66f4\u65b0\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">scores.replace(\"Eve\", 95);\nSystem.out.println(\"Eve's updated score: \" + scores.get(\"Eve\")); \/\/ \u51fa\u529b: Eve's updated score: 95\n\n\/\/ \u5b58\u5728\u3057\u306a\u3044\u30ad\u30fc\u306b\u5bfe\u3057\u3066replace()\u3092\u4f7f\u7528\nboolean replaced = scores.replace(\"Frank\", 80, 85);\nSystem.out.println(\"Frank's score replaced: \" + replaced); \/\/ \u51fa\u529b: Frank's score replaced: false<\/pre>\n\n\n<div id=\"sgb-css-id-76\">\n<p>HashMap\u306e\u4e3b\u8981\u30e1\u30bd\u30c3\u30c9\u3068\u57fa\u672c\u64cd\u4f5c\u3092\u7406\u89e3\u3059\u308b\u3053\u3068\u3067\u3001\u52b9\u7387\u7684\u306a\u30c7\u30fc\u30bf\u7ba1\u7406\u304c\u53ef\u80fd\u306b\u306a\u308a\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001HashMap\u306e\u5185\u90e8\u69cb\u9020\u3068\u52d5\u4f5c\u539f\u7406\u306b\u3064\u3044\u3066\u8a73\u3057\u304f\u898b\u3066\u3044\u304d\u307e\u3059\u3002\u3053\u308c\u306b\u3088\u308a\u3001\u306a\u305cHashMap\u304c\u3053\u308c\u307b\u3069\u52b9\u7387\u7684\u306a\u306e\u304b\u3001\u305d\u306e\u79d8\u5bc6\u304c\u660e\u3089\u304b\u306b\u306a\u308b\u3067\u3057\u3087\u3046\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-77\">\n<h2 class=\"wp-block-heading\" id=\"i-24\">3. HashMap\u306e\u5185\u90e8\u69cb\u9020\u3068\u52d5\u4f5c\u539f\u7406<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-78\">\n<p>HashMap\u306e\u52b9\u7387\u6027\u3068\u9ad8\u901f\u306a\u64cd\u4f5c\u306e\u79d8\u5bc6\u306f\u3001\u305d\u306e\u5de7\u5999\u306a\u5185\u90e8\u69cb\u9020\u3068\u52d5\u4f5c\u539f\u7406\u306b\u3042\u308a\u307e\u3059\u3002\u3053\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001HashMap\u306e\u5185\u90e8\u3067\u4f55\u304c\u8d77\u3053\u3063\u3066\u3044\u308b\u306e\u304b\u3001\u8a73\u3057\u304f\u898b\u3066\u3044\u304d\u307e\u3057\u3087\u3046\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-79\">\n<h3 class=\"wp-block-heading\" id=\"i-25\">3.1 \u30cf\u30c3\u30b7\u30e5\u30c6\u30fc\u30d6\u30eb\u306e\u4ed5\u7d44\u307f\uff1a\u9ad8\u901f\u30a2\u30af\u30bb\u30b9\u306e\u79d8\u5bc6<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-80\">\n<p>HashMap\u306f\u3001\u30cf\u30c3\u30b7\u30e5\u30c6\u30fc\u30d6\u30eb\u3068\u547c\u3070\u308c\u308b\u30c7\u30fc\u30bf\u69cb\u9020\u3092\u57fa\u76e4\u3068\u3057\u3066\u3044\u307e\u3059\u3002\u30cf\u30c3\u30b7\u30e5\u30c6\u30fc\u30d6\u30eb\u306f\u3001\u30ad\u30fc\u3092\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u306b\u5909\u63db\u3057\u3066\u5024\u3092\u683c\u7d0d\u3059\u308b\u914d\u5217\u30d9\u30fc\u30b9\u306e\u30c7\u30fc\u30bf\u69cb\u9020\u3067\u3059\u3002<\/p>\n<\/div>\n\n\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">\u30cf\u30c3\u30b7\u30e5\u95a2\u6570\u306e\u5f79\u5272<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ol class=\"wp-block-list\"><div id=\"sgb-css-id-81\">\n<li>\u30ad\u30fc\u306ehashCode()\u30e1\u30bd\u30c3\u30c9\u3092\u547c\u3073\u51fa\u3057\u3066\u30cf\u30c3\u30b7\u30e5\u5024\u3092\u751f\u6210<\/li>\n<\/div>\n\n\n<li>\u30cf\u30c3\u30b7\u30e5\u5024\u3092\u914d\u5217\u306e\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u306b\u5909\u63db<\/li>\n<\/ol>\n<\/div><\/div>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">int index = (n - 1) &amp; hash(key);<\/pre>\n\n\n\n<p>\u3053\u3053\u3067\u3001<code>n<\/code>\u306f\u914d\u5217\u306e\u9577\u3055\uff08\u5e38\u306b2\u306e\u7d2f\u4e57\uff09\u3001<code>hash(key)<\/code>\u306f\u30ad\u30fc\u306e\u30cf\u30c3\u30b7\u30e5\u5024\u3067\u3059\u3002<\/p>\n\n\n<div id=\"sgb-css-id-82\">\n<p>HashMap\u306f\u4ee5\u4e0b\u306e\u8981\u7d20\u3067\u69cb\u6210\u3055\u308c\u3066\u3044\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">HashMap\u306e\u5185\u90e8\u69cb\u9020<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ol class=\"wp-block-list\"><div id=\"sgb-css-id-83\">\n<li><strong>\u914d\u5217\uff08\u30d0\u30b1\u30c3\u30c8\uff09<\/strong>\uff1a \u30c7\u30d5\u30a9\u30eb\u30c8\u306e\u521d\u671f\u5bb9\u91cf\u306f16<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-84\">\n<li><strong>\u30a8\u30f3\u30c8\u30ea<\/strong>\uff1a \u30ad\u30fc\u3001\u5024\u3001\u30cf\u30c3\u30b7\u30e5\u5024\u3092\u4fdd\u6301\u3059\u308b\u30ce\u30fc\u30c9<\/li>\n<\/div>\n\n\n<li><strong>\u30ea\u30f3\u30af\u30c9\u30ea\u30b9\u30c8\u307e\u305f\u306f\u8d64\u9ed2\u6728<\/strong>\uff1a \u5404\u30d0\u30b1\u30c3\u30c8\u5185\u306e\u885d\u7a81\u3092\u89e3\u6c7a\u3059\u308b\u305f\u3081\u306e\u30c7\u30fc\u30bf\u69cb\u9020<\/li>\n<\/ol>\n<\/div><\/div>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">&lt;antArtifact identifier=\"hashmap-structure\" type=\"image\/svg+xml\" title=\"HashMap\u306e\u5185\u90e8\u69cb\u9020\"&gt;\n&lt;svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewBox=\"0 0 500 300\"&gt;\n  &lt;rect x=\"10\" y=\"10\" width=\"480\" height=\"280\" fill=\"none\" stroke=\"black\" \/&gt;\n  &lt;line x1=\"10\" y1=\"50\" x2=\"490\" y2=\"50\" stroke=\"black\" stroke-dasharray=\"5,5\" \/&gt;\n  &lt;text x=\"20\" y=\"35\" font-family=\"Arial\" font-size=\"14\"&gt;\u30d0\u30b1\u30c3\u30c8\u914d\u5217&lt;\/text&gt;\n  &lt;rect x=\"20\" y=\"60\" width=\"60\" height=\"30\" fill=\"lightblue\" stroke=\"black\" \/&gt;\n  &lt;text x=\"35\" y=\"80\" font-family=\"Arial\" font-size=\"12\"&gt;0&lt;\/text&gt;\n  &lt;rect x=\"20\" y=\"100\" width=\"60\" height=\"30\" fill=\"lightblue\" stroke=\"black\" \/&gt;\n  &lt;text x=\"35\" y=\"120\" font-family=\"Arial\" font-size=\"12\"&gt;1&lt;\/text&gt;\n  &lt;rect x=\"20\" y=\"140\" width=\"60\" height=\"30\" fill=\"lightblue\" stroke=\"black\" \/&gt;\n  &lt;text x=\"35\" y=\"160\" font-family=\"Arial\" font-size=\"12\"&gt;2&lt;\/text&gt;\n  &lt;text x=\"45\" y=\"200\" font-family=\"Arial\" font-size=\"14\"&gt;...&lt;\/text&gt;\n  &lt;rect x=\"20\" y=\"220\" width=\"60\" height=\"30\" fill=\"lightblue\" stroke=\"black\" \/&gt;\n  &lt;text x=\"30\" y=\"240\" font-family=\"Arial\" font-size=\"12\"&gt;n-1&lt;\/text&gt;\n  &lt;path d=\"M 80 75 L 120 75 L 120 115 L 160 115\" fill=\"none\" stroke=\"black\" \/&gt;\n  &lt;rect x=\"160\" y=\"100\" width=\"100\" height=\"30\" fill=\"lightgreen\" stroke=\"black\" \/&gt;\n  &lt;text x=\"170\" y=\"120\" font-family=\"Arial\" font-size=\"12\"&gt;key1 | value1&lt;\/text&gt;\n  &lt;path d=\"M 260 115 L 300 115 L 300 155 L 340 155\" fill=\"none\" stroke=\"black\" \/&gt;\n  &lt;rect x=\"340\" y=\"140\" width=\"100\" height=\"30\" fill=\"lightgreen\" stroke=\"black\" \/&gt;\n  &lt;text x=\"350\" y=\"160\" font-family=\"Arial\" font-size=\"12\"&gt;key2 | value2&lt;\/text&gt;\n  &lt;path d=\"M 80 235 L 120 235 L 120 195 L 160 195\" fill=\"none\" stroke=\"black\" \/&gt;\n  &lt;rect x=\"160\" y=\"180\" width=\"100\" height=\"30\" fill=\"lightgreen\" stroke=\"black\" \/&gt;\n  &lt;text x=\"170\" y=\"200\" font-family=\"Arial\" font-size=\"12\"&gt;key3 | value3&lt;\/text&gt;\n  &lt;path d=\"M 260 195 L 300 195 L 300 235 L 340 235\" fill=\"none\" stroke=\"black\" \/&gt;\n  &lt;rect x=\"340\" y=\"220\" width=\"100\" height=\"30\" fill=\"lightgreen\" stroke=\"black\" \/&gt;\n  &lt;text x=\"350\" y=\"240\" font-family=\"Arial\" font-size=\"12\"&gt;key4 | value4&lt;\/text&gt;\n&lt;\/svg&gt;<\/pre>\n\n\n<div id=\"sgb-css-id-85\">\n<h3 class=\"wp-block-heading\" id=\"i-26\">3.2 LoadFactor\u3068Rehash\uff1a\u81ea\u52d5\u7684\u306a\u6027\u80fd\u6700\u9069\u5316<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-86\">\n<p>HashMap\u306f\u3001\u52b9\u7387\u7684\u306a\u64cd\u4f5c\u3092\u7dad\u6301\u3059\u308b\u305f\u3081\u306b\u81ea\u52d5\u7684\u306b\u6700\u9069\u5316\u3092\u884c\u3044\u307e\u3059\u3002\u3053\u306e\u904e\u7a0b\u3067\u91cd\u8981\u306a\u5f79\u5272\u3092\u679c\u305f\u3059\u306e\u304c\u3001LoadFactor\uff08\u8ca0\u8377\u4fc2\u6570\uff09\u3068\u30ea\u30cf\u30c3\u30b7\u30e5\u3067\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-87\">\n<p>LoadFactor\u306f\u3001HashMap\u5bb9\u91cf\u306b\u5bfe\u3059\u308b\u4f7f\u7528\u7387\u306e\u95be\u5024\u3092\u6c7a\u5b9a\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">LoadFactor\uff08\u8ca0\u8377\u4fc2\u6570\uff09<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ul class=\"wp-block-list\"><div id=\"sgb-css-id-88\">\n<li>\u30c7\u30d5\u30a9\u30eb\u30c8\u5024\uff1a 0.75\uff0875%\uff09<\/li>\n<\/div>\n\n\n<li>\u8a08\u7b97\u5f0f\uff1a \u5b9f\u969b\u306e\u8981\u7d20\u6570 \/ \u73fe\u5728\u306e\u5bb9\u91cf<\/li>\n<\/ul>\n<\/div><\/div>\n\n\n<div id=\"sgb-css-id-89\">\n<p>LoadFactor\u3092\u8d85\u3048\u308b\u3068\u3001HashMap\u306f\u5bb9\u91cf\u3092\u5897\u3084\u3057\u3066\u30ea\u30cf\u30c3\u30b7\u30e5\u3092\u884c\u3044\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">\u30ea\u30cf\u30c3\u30b7\u30e5\uff08rehash\uff09\u306e\u30d7\u30ed\u30bb\u30b9<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ol class=\"wp-block-list\"><div id=\"sgb-css-id-90\">\n<li>\u65b0\u3057\u3044\u5bb9\u91cf\u3092\u8a08\u7b97\uff08\u901a\u5e38\u306f\u73fe\u5728\u306e2\u500d\uff09<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-91\">\n<li>\u65b0\u3057\u3044\u914d\u5217\u3092\u4f5c\u6210<\/li>\n<\/div>\n\n\n<li>\u5168\u3066\u306e\u8981\u7d20\u3092\u65b0\u3057\u3044\u914d\u5217\u306b\u518d\u914d\u7f6e<\/li>\n<\/ol>\n<\/div><\/div>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/\/ \u30ea\u30cf\u30c3\u30b7\u30e5\u306e\u7c21\u7565\u5316\u3055\u308c\u305f\u30d7\u30ed\u30bb\u30b9\nvoid resize() {\n    Entry[] oldTable = table;\n    int oldCapacity = oldTable.length;\n    int newCapacity = oldCapacity * 2;\n    Entry[] newTable = new Entry[newCapacity];\n    for (Entry e : oldTable) {\n        while(e != null) {\n            Entry next = e.next;\n            int i = indexFor(e.hash, newCapacity);\n            e.next = newTable[i];\n            newTable[i] = e;\n            e = next;\n        }\n    }\n    table = newTable;\n}<\/pre>\n\n\n\n<p>\u30ea\u30cf\u30c3\u30b7\u30e5\u306f\u8a08\u7b97\u30b3\u30b9\u30c8\u304c\u9ad8\u3044\u305f\u3081\u3001\u521d\u671f\u5bb9\u91cf\u3092\u9069\u5207\u306b\u8a2d\u5b9a\u3059\u308b\u3053\u3068\u304c\u91cd\u8981\u3067\u3059\u3002<\/p>\n\n\n<div id=\"sgb-css-id-92\">\n<h4 class=\"wp-block-heading\" id=\"i-27\">\u30cf\u30c3\u30b7\u30e5\u885d\u7a81\u3068\u305d\u306e\u89e3\u6c7a<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-93\">\n<p>\u30cf\u30c3\u30b7\u30e5\u885d\u7a81\u306f\u3001\u7570\u306a\u308b\u30ad\u30fc\u304c\u540c\u3058\u30cf\u30c3\u30b7\u30e5\u5024\uff08\u3064\u307e\u308a\u540c\u3058\u30d0\u30b1\u30c3\u30c8\uff09\u306b\u5272\u308a\u5f53\u3066\u3089\u308c\u308b\u73fe\u8c61\u3067\u3059\u3002HashMap\u306f\u30c1\u30a7\u30a4\u30cb\u30f3\u30b0\u3068\u3044\u3046\u65b9\u6cd5\u3067\u885d\u7a81\u3092\u89e3\u6c7a\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-95\">\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">\u30cf\u30c3\u30b7\u30e5\u885d\u7a81\u306e\u89e3\u6c7a\u65b9\u6cd5<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ol class=\"wp-block-list\"><div id=\"sgb-css-id-94\">\n<li>Java 8\u672a\u6e80\uff1a \u5404\u30d0\u30b1\u30c3\u30c8\u306b\u30ea\u30f3\u30af\u30c9\u30ea\u30b9\u30c8\u3092\u4f7f\u7528<\/li>\n<\/div>\n\n\n<li>Java 8\u4ee5\u964d\uff1a \u30d0\u30b1\u30c3\u30c8\u5185\u306e\u8981\u7d20\u6570\u304c8\u3092\u8d85\u3048\u308b\u3068\u3001\u30ea\u30f3\u30af\u30c9\u30ea\u30b9\u30c8\u304b\u3089\u8d64\u9ed2\u6728\u306b\u5909\u63db<\/li>\n<\/ol>\n<\/div><\/div>\n<\/div>\n\n<div id=\"sgb-css-id-96\">\n<p>\u8d64\u9ed2\u6728\u306e\u5c0e\u5165\u306b\u3088\u308a\u3001\u6700\u60aa\u6642\u9593\u8907\u96d1\u5ea6\u304cO(log n)\u306b\u6539\u5584\u3055\u308c\u307e\u3057\u305f\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-97\">\n<h3 class=\"wp-block-heading\" id=\"i-28\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3078\u306e\u5f71\u97ff<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-98\">\n<p>HashMap\u306e\u5185\u90e8\u69cb\u9020\u306f\u3001\u305d\u306e\u6027\u80fd\u306b\u76f4\u63a5\u5f71\u97ff\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-101\">\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3078\u306e\u5f71\u97ff<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ol class=\"wp-block-list\"><div id=\"sgb-css-id-99\">\n<li><strong>\u9069\u5207\u306a\u30cf\u30c3\u30b7\u30e5\u95a2\u6570<\/strong>\uff1a \u30ad\u30fc\u3092\u5747\u7b49\u306b\u5206\u6563\u3055\u305b\u308b\u3053\u3068\u304c\u91cd\u8981<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-100\">\n<li><strong>LoadFactor<\/strong>\uff1a \u4f4e\u3059\u304e\u308b\u3068\u30e1\u30e2\u30ea\u6d88\u8cbb\u304c\u5897\u52a0\u3001\u9ad8\u3059\u304e\u308b\u3068\u885d\u7a81\u304c\u5897\u52a0<\/li>\n<\/div>\n\n\n<li><strong>\u521d\u671f\u5bb9\u91cf<\/strong>\uff1a \u4e88\u60f3\u3055\u308c\u308b\u8981\u7d20\u6570\u306b\u57fa\u3065\u3044\u3066\u9069\u5207\u306b\u8a2d\u5b9a\u3059\u308b\u3053\u3068\u3067\u3001\u4e0d\u8981\u306a\u30ea\u30cf\u30c3\u30b7\u30e5\u3092\u56de\u907f<\/li>\n<\/ol>\n<\/div><\/div>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/\/ \u4e88\u60f3\u3055\u308c\u308b\u8981\u7d20\u6570\u304c1000\u306e\u5834\u5408\u306e\u521d\u671f\u5316\nint expectedElements = 1000;\nfloat loadFactor = 0.75f;\nint initialCapacity = (int) (expectedElements \/ loadFactor);\nHashMap&lt;String, Integer&gt; map = new HashMap&lt;&gt;(initialCapacity, loadFactor);<\/pre>\n\n\n<div id=\"sgb-css-id-102\">\n<p>HashMap\u306e\u5185\u90e8\u69cb\u9020\u3068\u52d5\u4f5c\u539f\u7406\u3092\u7406\u89e3\u3059\u308b\u3053\u3068\u3067\u3001\u3088\u308a\u52b9\u7387\u7684\u306a\u30b3\u30fc\u30c9\u3092\u66f8\u304f\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u3053\u308c\u3089\u306e\u77e5\u8b58\u3092\u6d3b\u304b\u3057\u305f\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u30c1\u30e5\u30fc\u30cb\u30f3\u30b0\u306e\u65b9\u6cd5\u306b\u3064\u3044\u3066\u8a73\u3057\u304f\u898b\u3066\u3044\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-103\">\n<h2 class=\"wp-block-heading\" id=\"i-29\">4. HashMap\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u30c1\u30e5\u30fc\u30cb\u30f3\u30b0<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-104\">\n<p>HashMap\u306f\u975e\u5e38\u306b\u52b9\u7387\u7684\u306a\u30c7\u30fc\u30bf\u69cb\u9020\u3067\u3059\u304c\u3001\u9069\u5207\u306b\u4f7f\u7528\u3057\u306a\u3044\u3068\u6027\u80fd\u304c\u4f4e\u4e0b\u3059\u308b\u53ef\u80fd\u6027\u304c\u3042\u308a\u307e\u3059\u3002\u3053\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001HashMap\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u6700\u9069\u5316\u3059\u308b\u305f\u3081\u306e\u91cd\u8981\u306a\u30c6\u30af\u30cb\u30c3\u30af\u3092\u7d39\u4ecb\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-105\">\n<h3 class=\"wp-block-heading\" id=\"i-30\">4.1 \u521d\u671f\u5bb9\u91cf\u306e\u9069\u5207\u306a\u8a2d\u5b9a\uff1a\u30e1\u30e2\u30ea\u52b9\u7387\u3092\u9ad8\u3081\u308b<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-106\">\n<p>HashMap\u306e\u521d\u671f\u5bb9\u91cf\u3092\u9069\u5207\u306b\u8a2d\u5b9a\u3059\u308b\u3053\u3068\u3067\u3001\u4e0d\u8981\u306a\u30ea\u30cf\u30c3\u30b7\u30e5\u3092\u907f\u3051\u3001\u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u3092\u6700\u9069\u5316\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/\/ \u4e88\u60f3\u3055\u308c\u308b\u8981\u7d20\u6570\u306b\u57fa\u3065\u3044\u3066\u521d\u671f\u5bb9\u91cf\u3092\u8a2d\u5b9a\nint expectedElements = 1000;\nfloat loadFactor = 0.75f;\nint initialCapacity = (int) (expectedElements \/ loadFactor);\nHashMap&lt;String, Integer&gt; optimizedMap = new HashMap&lt;&gt;(initialCapacity, loadFactor);<\/pre>\n\n\n<div id=\"sgb-css-id-107\">\n<p>\u3053\u306e\u65b9\u6cd5\u306b\u3088\u308a\u3001HashMap\u4f5c\u6210\u6642\u306b\u9069\u5207\u306a\u5bb9\u91cf\u304c\u78ba\u4fdd\u3055\u308c\u3001\u8981\u7d20\u8ffd\u52a0\u6642\u306e\u983b\u7e41\u306a\u30ea\u30cf\u30c3\u30b7\u30e5\u3092\u9632\u304e\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-108\">\n<h3 class=\"wp-block-heading\" id=\"i-31\">4.2 \u30ab\u30b9\u30bf\u30e0\u30ad\u30fc\u306e\u5229\u7528\uff1ahashCode()\u3068equals()\u306e\u30aa\u30fc\u30d0\u30fc\u30e9\u30a4\u30c9<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-109\">\n<p>\u30ab\u30b9\u30bf\u30e0\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u30ad\u30fc\u3068\u3057\u3066\u4f7f\u7528\u3059\u308b\u5834\u5408\u3001hashCode()\u3068equals()\u30e1\u30bd\u30c3\u30c9\u3092\u9069\u5207\u306b\u30aa\u30fc\u30d0\u30fc\u30e9\u30a4\u30c9\u3059\u308b\u3053\u3068\u304c\u91cd\u8981\u3067\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">public class CustomKey {\n    private final String id;\n    private final int value;\n\n    \/\/ \u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u3001\u30b2\u30c3\u30bf\u30fc\u306f\u7701\u7565\n\n    @Override\n    public int hashCode() {\n        return Objects.hash(id, value);\n    }\n\n    @Override\n    public boolean equals(Object obj) {\n        if (this == obj) return true;\n        if (obj == null || getClass() != obj.getClass()) return false;\n        CustomKey other = (CustomKey) obj;\n        return Objects.equals(id, other.id) &amp;&amp; value == other.value;\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-110\">\n<p>\u52b9\u7387\u7684\u306ahashCode()\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u30ad\u30fc\u306e\u5747\u7b49\u306a\u5206\u5e03\u3092\u4fc3\u9032\u3057\u3001\u885d\u7a81\u3092\u6e1b\u5c11\u3055\u305b\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-111\">\n<h3 class=\"wp-block-heading\" id=\"i-32\">HashMap\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u306b\u5f71\u97ff\u3092\u4e0e\u3048\u308b\u8981\u56e0<\/h3>\n<\/div>\n\n\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3078\u306e\u5f71\u97ff\u8981\u56e0<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ol class=\"wp-block-list\"><div id=\"sgb-css-id-112\">\n<li><strong>\u521d\u671f\u5bb9\u91cf<\/strong>\uff1a \u5c0f\u3055\u3059\u304e\u308b\u3068\u983b\u7e41\u306a\u30ea\u30cf\u30c3\u30b7\u30e5\u3001\u5927\u304d\u3059\u304e\u308b\u3068\u30e1\u30e2\u30ea\u306e\u7121\u99c4<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-113\">\n<li><strong>LoadFactor<\/strong>\uff1a \u30c7\u30d5\u30a9\u30eb\u30c8(0.75)\u304c\u9069\u5207\u3001\u8abf\u6574\u306f\u614e\u91cd\u306b<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-114\">\n<li><strong>\u30cf\u30c3\u30b7\u30e5\u95a2\u6570\u306e\u54c1\u8cea<\/strong>\uff1a \u5747\u7b49\u306a\u5206\u5e03\u304c\u91cd\u8981<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-115\">\n<li><strong>\u30ad\u30fc\u306e\u9078\u629e<\/strong>\uff1a \u30a4\u30df\u30e5\u30fc\u30bf\u30d6\u30eb\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u304c\u7406\u60f3\u7684<\/li>\n<\/div>\n\n\n<li><strong>\u30ea\u30cf\u30c3\u30b7\u30e5\u306e\u983b\u5ea6<\/strong>\uff1a \u904e\u5ea6\u306a\u30ea\u30cf\u30c3\u30b7\u30e5\u306f\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u306b\u60aa\u5f71\u97ff<\/li>\n<\/ol>\n<\/div><\/div>\n\n\n<div id=\"sgb-css-id-116\">\n<h3 class=\"wp-block-heading\" id=\"i-33\">\u52b9\u7387\u7684\u306a\u30ad\u30fc\u9078\u629e<\/h3>\n<\/div>\n\n\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">\u52b9\u7387\u7684\u306a\u30ad\u30fc\u9078\u629e<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ol class=\"wp-block-list\"><div id=\"sgb-css-id-117\">\n<li>\u30a4\u30df\u30e5\u30fc\u30bf\u30d6\u30eb\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u4f7f\u7528\uff08String, Integer\u7b49\uff09<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-118\">\n<li>hashCode()\u304c\u5341\u5206\u306b\u5206\u6563\u3055\u308c\u305f\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u9078\u629e<\/li>\n<\/div>\n\n\n<li>\u53ef\u80fd\u306a\u9650\u308a\u3001\u30d7\u30ea\u30df\u30c6\u30a3\u30d6\u30e9\u30c3\u30d1\u30fc\u30af\u30e9\u30b9\u3084\u6587\u5b57\u5217\u3092\u512a\u5148<\/li>\n<\/ol>\n<\/div><\/div>\n\n\n<div id=\"sgb-css-id-119\">\n<h3 class=\"wp-block-heading\" id=\"i-34\">\u30d0\u30b1\u30c3\u30c8\u306e\u5206\u5e03\u5206\u6790<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-120\">\n<p>\u30d0\u30b1\u30c3\u30c8\u306e\u5206\u5e03\u3092\u5206\u6790\u3059\u308b\u3053\u3068\u3067\u3001\u30cf\u30c3\u30b7\u30e5\u95a2\u6570\u306e\u52b9\u7387\u6027\u3092\u8a55\u4fa1\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">public static void analyzeDistribution(HashMap&lt;?, ?&gt; map) {\n    int buckets = 0;\n    int maxSize = 0;\n    int empty = 0;\n    for (var bucket : map.values().toArray()) {\n        int size = bucket == null ? 0 : ((Map.Entry)bucket).getValue() == null ? 1 : ((TreeNode)bucket).size();\n        buckets += size;\n        if (size &gt; maxSize) maxSize = size;\n        if (size == 0) empty++;\n    }\n    System.out.printf(\"Bucket\u60c5\u5831: \u5408\u8a08=%d, \u6700\u5927\u30b5\u30a4\u30ba=%d, \u7a7a=%d%n\", buckets, maxSize, empty);\n}<\/pre>\n\n\n\n<p>\u3053\u306e\u5206\u6790\u7d50\u679c\u3092\u57fa\u306b\u3001\u30ad\u30fc\u306e\u9078\u629e\u3084\u30cf\u30c3\u30b7\u30e5\u95a2\u6570\u3092\u6700\u9069\u5316\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n<div id=\"sgb-css-id-121\">\n<h3 class=\"wp-block-heading\" id=\"i-35\">Java 8\u4ee5\u964d\u306e\u6700\u9069\u5316\u6a5f\u80fd\u306e\u6d3b\u7528<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-122\">\n<p>Java 8\u3067\u5c0e\u5165\u3055\u308c\u305f\u65b0\u3057\u3044\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u7528\u3059\u308b\u3068\u3001\u7279\u5b9a\u306e\u64cd\u4f5c\u3092\u6700\u9069\u5316\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/\/ \u5024\u304c\u5b58\u5728\u3057\u306a\u3044\u5834\u5408\u306b\u306e\u307f\u8a08\u7b97\u3057\u3066\u8ffd\u52a0\nmap.computeIfAbsent(key, k -&gt; expensiveOperation(k));\n\n\/\/ \u30ad\u30fc\u304c\u5b58\u5728\u3059\u308b\u5834\u5408\u3001\u5024\u3092\u66f4\u65b0\nmap.merge(key, 1, Integer::sum);\n\n\/\/ \u3059\u3079\u3066\u306e\u5024\u3092\u5909\u63db\nmap.replaceAll((k, v) -&gt; v * 2);<\/pre>\n\n\n\n<p>\u3053\u308c\u3089\u306e\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u6761\u4ef6\u30c1\u30a7\u30c3\u30af\u3068\u66f4\u65b0\u30921\u56de\u306e\u64cd\u4f5c\u3067\u884c\u3046\u305f\u3081\u3001\u52b9\u7387\u7684\u3067\u3059\u3002<\/p>\n\n\n<div id=\"sgb-css-id-123\">\n<h3 class=\"wp-block-heading\" id=\"i-36\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u30c1\u30e5\u30fc\u30cb\u30f3\u30b0\u306e\u52b9\u679c\u6e2c\u5b9a<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-124\">\n<p>\u6700\u9069\u5316\u306e\u52b9\u679c\u3092\u78ba\u8a8d\u3059\u308b\u306b\u306f\u3001\u7c21\u5358\u306a\u30d9\u30f3\u30c1\u30de\u30fc\u30af\u3092\u884c\u3046\u3053\u3068\u304c\u6709\u52b9\u3067\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">long start = System.nanoTime();\n\/\/ \u6e2c\u5b9a\u3057\u305f\u3044\u64cd\u4f5c\nlong end = System.nanoTime();\nSystem.out.println(\"\u5b9f\u884c\u6642\u9593: \" + (end - start) + \" ns\");<\/pre>\n\n\n<div id=\"sgb-css-id-125\">\n<p>\u3088\u308a\u6b63\u78ba\u306a\u6e2c\u5b9a\u306b\u306f\u3001JMH\uff08Java Microbenchmark Harness\uff09\u306a\u3069\u306e\u5c02\u7528\u30c4\u30fc\u30eb\u306e\u4f7f\u7528\u3092\u691c\u8a0e\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-126\">\n<p>HashMap\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u30c1\u30e5\u30fc\u30cb\u30f3\u30b0\u306f\u3001\u9069\u5207\u306a\u521d\u671f\u8a2d\u5b9a\u3001\u52b9\u7387\u7684\u306a\u30ad\u30fc\u306e\u9078\u629e\u3001\u305d\u3057\u3066\u65b0\u6a5f\u80fd\u306e\u6d3b\u7528\u306b\u3088\u3063\u3066\u5b9f\u73fe\u3067\u304d\u307e\u3059\u3002\u3053\u308c\u3089\u306e\u30c6\u30af\u30cb\u30c3\u30af\u3092\u9069\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u306e\u5168\u4f53\u7684\u306a\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u5927\u5e45\u306b\u5411\u4e0a\u3055\u305b\u308b\u3053\u3068\u304c\u3067\u304d\u308b\u3067\u3057\u3087\u3046\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-127\">\n<h2 class=\"wp-block-heading\" id=\"i-37\">5. HashMap\u3068\u4ed6\u306eMap\u5b9f\u88c5\u306e\u6bd4\u8f03<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-128\">\n<p>Java\u306b\u306f\u3001HashMap\u4ee5\u5916\u306b\u3082\u69d8\u3005\u306aMap\u5b9f\u88c5\u304c\u5b58\u5728\u3057\u307e\u3059\u3002\u305d\u308c\u305e\u308c\u306e\u5b9f\u88c5\u306b\u306f\u72ec\u81ea\u306e\u7279\u5fb4\u304c\u3042\u308a\u3001\u9069\u5207\u306a\u4f7f\u7528\u5834\u9762\u304c\u7570\u306a\u308a\u307e\u3059\u3002\u3053\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u4e3b\u8981\u306aMap\u5b9f\u88c5\u3092\u6bd4\u8f03\u3057\u3001\u305d\u308c\u305e\u308c\u306e\u9577\u6240\u3068\u77ed\u6240\u3092\u89e3\u8aac\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-129\">\n<h3 class=\"wp-block-heading\" id=\"i-38\">5.1 HashMap\u3068TreeMap\uff1a\u9806\u5e8f\u4ed8\u3051\u306e\u9055\u3044\u3068\u4f7f\u3044\u5206\u3051<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-130\">\n<p>HashMap\u3068TreeMap\u306f\u3001\u6700\u3082\u4e00\u822c\u7684\u306b\u4f7f\u7528\u3055\u308c\u308b2\u3064\u306eMap\u5b9f\u88c5\u3067\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-134\">\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">HashMap<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ul class=\"wp-block-list\"><div id=\"sgb-css-id-131\">\n<li>\u7279\u5fb4\uff1a\u30cf\u30c3\u30b7\u30e5\u30c6\u30fc\u30d6\u30eb\u30d9\u30fc\u30b9\u3001\u9806\u5e8f\u306a\u3057<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-132\">\n<li>\u9577\u6240\uff1a\u307b\u3068\u3093\u3069\u306e\u64cd\u4f5c\u304c\u5e73\u5747O(1)\u306e\u6642\u9593\u8907\u96d1\u5ea6<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-133\">\n<li>\u77ed\u6240\uff1a\u30ad\u30fc\u306e\u9806\u5e8f\u3092\u4fdd\u6301\u3057\u306a\u3044<\/li>\n<\/div><\/ul>\n<\/div><\/div>\n<\/div>\n\n\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">TreeMap<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ul class=\"wp-block-list\"><div id=\"sgb-css-id-135\">\n<li>\u7279\u5fb4\uff1a\u8d64\u9ed2\u6728\u30d9\u30fc\u30b9\u3001\u30bd\u30fc\u30c8\u9806<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-136\">\n<li>\u9577\u6240\uff1a\u30ad\u30fc\u304c\u5e38\u306b\u30bd\u30fc\u30c8\u3055\u308c\u305f\u72b6\u614b\u3067\u7dad\u6301\u3055\u308c\u308b<\/li>\n<\/div>\n\n\n<li>\u77ed\u6240\uff1a\u4e3b\u8981\u306a\u64cd\u4f5c\u304cO(log n)\u306e\u6642\u9593\u8907\u96d1\u5ea6<\/li>\n<\/ul>\n<\/div><\/div>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">Map&lt;String, Integer&gt; hashMap = new HashMap&lt;&gt;();\nMap&lt;String, Integer&gt; treeMap = new TreeMap&lt;&gt;();\n\n\/\/ HashMap\u306f\u633f\u5165\u9806\u3092\u4fdd\u6301\u3057\u306a\u3044\nhashMap.put(\"B\", 2);\nhashMap.put(\"A\", 1);\nhashMap.put(\"C\", 3);\nSystem.out.println(hashMap.keySet()); \/\/ \u51fa\u529b\u9806\u306f\u4fdd\u8a3c\u3055\u308c\u306a\u3044\n\n\/\/ TreeMap\u306f\u30ad\u30fc\u3067\u30bd\u30fc\u30c8\u3055\u308c\u308b\ntreeMap.put(\"B\", 2);\ntreeMap.put(\"A\", 1);\ntreeMap.put(\"C\", 3);\nSystem.out.println(treeMap.keySet()); \/\/ \u5fc5\u305a [A, B, C] \u306e\u9806\u3067\u51fa\u529b<\/pre>\n\n\n<div id=\"sgb-css-id-137\">\n<h3 class=\"wp-block-heading\" id=\"i-39\">5.2 HashMap\u3068LinkedHashMap\uff1a\u633f\u5165\u9806\u5e8f\u306e\u7dad\u6301\u304c\u5fc5\u8981\u306a\u5834\u5408<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-138\">\n<p>LinkedHashMap\u306f\u3001HashMap\u306e\u7279\u6027\u3092\u4fdd\u3061\u3064\u3064\u3001\u8981\u7d20\u306e\u633f\u5165\u9806\u5e8f\u3082\u7dad\u6301\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-141\">\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">LinkedHashMap<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ul class=\"wp-block-list\"><div id=\"sgb-css-id-139\">\n<li>\u7279\u5fb4\uff1a\u30cf\u30c3\u30b7\u30e5\u30c6\u30fc\u30d6\u30eb + \u30ea\u30f3\u30af\u30c9\u30ea\u30b9\u30c8<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-140\">\n<li>\u9577\u6240\uff1a\u633f\u5165\u9806\u307e\u305f\u306f\u6700\u8fd1\u4f7f\u7528\u9806\u3092\u4fdd\u6301\u3057\u3064\u3064\u3001\u9ad8\u901f\u306a\u30a2\u30af\u30bb\u30b9\u3092\u63d0\u4f9b<\/li>\n<\/div>\n\n\n<li>\u77ed\u6240\uff1aHashMap\u3088\u308a\u3082\u308f\u305a\u304b\u306b\u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u304c\u591a\u3044<\/li>\n<\/ul>\n<\/div><\/div>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">Map&lt;String, Integer&gt; linkedHashMap = new LinkedHashMap&lt;&gt;();\nlinkedHashMap.put(\"B\", 2);\nlinkedHashMap.put(\"A\", 1);\nlinkedHashMap.put(\"C\", 3);\nSystem.out.println(linkedHashMap.keySet()); \/\/ \u5fc5\u305a [B, A, C] \u306e\u9806\u3067\u51fa\u529b<\/pre>\n\n\n<div id=\"sgb-css-id-142\">\n<h3 class=\"wp-block-heading\" id=\"i-40\">\u6027\u80fd\u6bd4\u8f03<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-143\">\n<p>\u5404Map\u5b9f\u88c5\u306e\u4e3b\u8981\u64cd\u4f5c\u306e\u6642\u9593\u8907\u96d1\u5ea6\u3092\u6bd4\u8f03\u3057\u3066\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\n<\/div>\n\n<div id=\"id-7b036a67-880d-4819-a620-971c85a31d4f\"><div id=\"sgb-css-id-144\">\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u64cd\u4f5c<\/th><th>HashMap<\/th><th>TreeMap<\/th><th>LinkedHashMap<\/th><\/tr><\/thead><tbody><tr><td>get<\/td><td>O(1)<\/td><td>O(log n)<\/td><td>O(1)<\/td><\/tr><tr><td>put<\/td><td>O(1)<\/td><td>O(log n)<\/td><td>O(1)<\/td><\/tr><tr><td>remove<\/td><td>O(1)<\/td><td>O(log n)<\/td><td>O(1)<\/td><\/tr><tr><td>containsKey<\/td><td>O(1)<\/td><td>O(log n)<\/td><td>O(1)<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div><\/div>\n\n<div id=\"sgb-css-id-145\">\n<h3 class=\"wp-block-heading\" id=\"i-41\">\u305d\u306e\u4ed6\u306e\u91cd\u8981\u306aMap\u5b9f\u88c5<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-147\">\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">ConcurrentHashMap<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ul class=\"wp-block-list\"><div id=\"sgb-css-id-146\">\n<li>\u7279\u5fb4\uff1a\u30b9\u30ec\u30c3\u30c9\u30bb\u30fc\u30d5\u306a\u30cf\u30c3\u30b7\u30e5\u30de\u30c3\u30d7<\/li>\n<\/div>\n\n\n<li>\u4f7f\u7528\u5834\u9762\uff1a\u8907\u6570\u30b9\u30ec\u30c3\u30c9\u304b\u3089\u540c\u6642\u306b\u30a2\u30af\u30bb\u30b9\u3055\u308c\u308b\u30c7\u30fc\u30bf\u306e\u7ba1\u7406<\/li>\n<\/ul>\n<\/div><\/div>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">Map&lt;String, Integer&gt; concurrentMap = new ConcurrentHashMap&lt;&gt;();\n\/\/ \u8907\u6570\u30b9\u30ec\u30c3\u30c9\u304b\u3089\u5b89\u5168\u306b\u64cd\u4f5c\u53ef\u80fd<\/pre>\n\n\n<div id=\"sgb-css-id-149\">\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">EnumMap<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ul class=\"wp-block-list\"><div id=\"sgb-css-id-148\">\n<li>\u7279\u5fb4\uff1aEnum\u578b\u3092\u30ad\u30fc\u3068\u3059\u308b\u7279\u6b8a\u306a\u30de\u30c3\u30d7<\/li>\n<\/div>\n\n\n<li>\u4f7f\u7528\u5834\u9762\uff1a\u30ad\u30fc\u304cEnum\u578b\u306e\u5834\u5408\u3001\u975e\u5e38\u306b\u52b9\u7387\u7684<\/li>\n<\/ul>\n<\/div><\/div>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">enum Day { MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY }\nMap&lt;Day, String&gt; schedule = new EnumMap&lt;&gt;(Day.class);\nschedule.put(Day.MONDAY, \"Work from home\");<\/pre>\n\n\n<div id=\"sgb-css-id-151\">\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">WeakHashMap<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ul class=\"wp-block-list\"><div id=\"sgb-css-id-150\">\n<li>\u7279\u5fb4\uff1a\u30a6\u30a3\u30fc\u30af\u30ea\u30d5\u30a1\u30ec\u30f3\u30b9\u3092\u4f7f\u7528\u3059\u308b\u30de\u30c3\u30d7<\/li>\n<\/div>\n\n\n<li>\u4f7f\u7528\u5834\u9762\uff1a\u30e1\u30e2\u30ea\u30bb\u30f3\u30b7\u30c6\u30a3\u30d6\u306a\u30ad\u30e3\u30c3\u30b7\u30e5\u306e\u5b9f\u88c5<\/li>\n<\/ul>\n<\/div><\/div>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">Map&lt;String, Resource&gt; resourceCache = new WeakHashMap&lt;&gt;();\n\/\/ \u30ea\u30bd\u30fc\u30b9\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306f\u30e1\u30e2\u30ea\u5727\u8feb\u6642\u306b\u81ea\u52d5\u7684\u306b\u89e3\u653e\u3055\u308c\u308b\u53ef\u80fd\u6027\u304c\u3042\u308b<\/pre>\n\n\n<div id=\"sgb-css-id-152\">\n<h3 class=\"wp-block-heading\" id=\"i-42\">\u9069\u5207\u306aMap\u5b9f\u88c5\u306e\u9078\u629e\u6307\u91dd<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-158\">\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">\u9069\u5207\u306aMap\u5b9f\u88c5\u306e\u9078\u629e\u6307\u91dd<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ol class=\"wp-block-list\"><div id=\"sgb-css-id-153\">\n<li>\u9ad8\u901f\u306a\u691c\u7d22\u304c\u6700\u512a\u5148\u306e\u5834\u5408\uff1aHashMap<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-154\">\n<li>\u30ad\u30fc\u306e\u30bd\u30fc\u30c8\u9806\u304c\u5fc5\u8981\u306a\u5834\u5408\uff1aTreeMap<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-155\">\n<li>\u633f\u5165\u9806\u3084\u6700\u8fd1\u4f7f\u7528\u9806\u306e\u7dad\u6301\u304c\u5fc5\u8981\u306a\u5834\u5408\uff1aLinkedHashMap<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-156\">\n<li>\u30de\u30eb\u30c1\u30b9\u30ec\u30c3\u30c9\u74b0\u5883\u3067\u306e\u4f7f\u7528\uff1aConcurrentHashMap<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-157\">\n<li>Enum\u3092\u30ad\u30fc\u3068\u3057\u3066\u4f7f\u7528\u3059\u308b\u5834\u5408\uff1aEnumMap<\/li>\n<\/div>\n\n\n<li>\u30e1\u30e2\u30ea\u30bb\u30f3\u30b7\u30c6\u30a3\u30d6\u306a\u30ad\u30e3\u30c3\u30b7\u30e5\u304c\u5fc5\u8981\u306a\u5834\u5408\uff1aWeakHashMap<\/li>\n<\/ol>\n<\/div><\/div>\n<\/div>\n\n<div id=\"sgb-css-id-159\">\n<p>\u9069\u5207\u306aMap\u5b9f\u88c5\u3092\u9078\u629e\u3059\u308b\u3053\u3068\u3067\u3001\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u306e\u6027\u80fd\u3068\u53ef\u8aad\u6027\u3092\u5927\u5e45\u306b\u5411\u4e0a\u3055\u305b\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002\u8981\u4ef6\u3092\u3088\u304f\u5206\u6790\u3057\u3001\u6700\u9069\u306a\u5b9f\u88c5\u3092\u9078\u3093\u3067\u304f\u3060\u3055\u3044\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-160\">\n<h2 class=\"wp-block-heading\" id=\"i-43\">6. HashMap\u306e\u5b9f\u8df5\u7684\u306a\u4f7f\u7528\u4f8b\u3068\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-161\">\n<p>HashMap\u306f\u975e\u5e38\u306b\u6c4e\u7528\u6027\u306e\u9ad8\u3044\u30c7\u30fc\u30bf\u69cb\u9020\u3067\u3059\u304c\u3001\u52b9\u679c\u7684\u306b\u4f7f\u7528\u3059\u308b\u306b\u306f\u3044\u304f\u3064\u304b\u306e\u30d1\u30bf\u30fc\u30f3\u3068\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\u3092\u7406\u89e3\u3059\u308b\u3053\u3068\u304c\u91cd\u8981\u3067\u3059\u3002\u3053\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u5b9f\u8df5\u7684\u306a\u4f7f\u7528\u4f8b\u3068\u3068\u3082\u306b\u3001HashMap\u3092\u6700\u5927\u9650\u306b\u6d3b\u7528\u3059\u308b\u305f\u3081\u306e\u30c6\u30af\u30cb\u30c3\u30af\u3092\u7d39\u4ecb\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-162\">\n<h3 class=\"wp-block-heading\" id=\"i-44\">6.1 \u983b\u51fa\u30d1\u30bf\u30fc\u30f3\uff1a\u30b0\u30eb\u30fc\u30d4\u30f3\u30b0\u3068\u30ab\u30a6\u30f3\u30c6\u30a3\u30f3\u30b0<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-163\">\n<p>HashMap\u306f\u3001\u30c7\u30fc\u30bf\u306e\u30b0\u30eb\u30fc\u30d4\u30f3\u30b0\u3084\u8981\u7d20\u306e\u30ab\u30a6\u30f3\u30c8\u306b\u975e\u5e38\u306b\u9069\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-164\">\n<h4 class=\"wp-block-heading\" id=\"i-45\">\u5358\u8a9e\u983b\u5ea6\u306e\u30ab\u30a6\u30f3\u30c8<\/h4>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">public static Map&lt;String, Integer&gt; countWords(String text) {\n    Map&lt;String, Integer&gt; wordCounts = new HashMap&lt;&gt;();\n    for (String word : text.split(\"\\\\s+\")) {\n        wordCounts.merge(word.toLowerCase(), 1, Integer::sum);\n    }\n    return wordCounts;\n}\n\n\/\/ \u4f7f\u7528\u4f8b\nString text = \"Hello world Hello Java World\";\nMap&lt;String, Integer&gt; counts = countWords(text);\nSystem.out.println(counts); \/\/ {world=2, java=1, hello=2}<\/pre>\n\n\n<div id=\"sgb-css-id-165\">\n<p>\u3053\u306e\u30d1\u30bf\u30fc\u30f3\u306f\u3001\u30c6\u30ad\u30b9\u30c8\u5206\u6790\u3084\u983b\u5ea6\u30d9\u30fc\u30b9\u306e\u30a2\u30eb\u30b4\u30ea\u30ba\u30e0\u3067\u975e\u5e38\u306b\u6709\u7528\u3067\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-166\">\n<h4 class=\"wp-block-heading\" id=\"i-46\">\u30ab\u30c6\u30b4\u30ea\u3054\u3068\u306e\u30a2\u30a4\u30c6\u30e0\u306e\u30b0\u30eb\u30fc\u30d4\u30f3\u30b0<\/h4>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">public static Map&lt;String, List&lt;String&gt;&gt; groupItems(List&lt;Item&gt; items) {\n    Map&lt;String, List&lt;String&gt;&gt; groupedItems = new HashMap&lt;&gt;();\n    for (Item item : items) {\n        groupedItems.computeIfAbsent(item.getCategory(), k -&gt; new ArrayList&lt;&gt;())\n                    .add(item.getName());\n    }\n    return groupedItems;\n}\n\n\/\/ \u4f7f\u7528\u4f8b\nList&lt;Item&gt; items = Arrays.asList(\n    new Item(\"Apple\", \"Fruit\"),\n    new Item(\"Banana\", \"Fruit\"),\n    new Item(\"Carrot\", \"Vegetable\")\n);\nMap&lt;String, List&lt;String&gt;&gt; grouped = groupItems(items);\nSystem.out.println(grouped); \/\/ {Fruit=[Apple, Banana], Vegetable=[Carrot]}<\/pre>\n\n\n<div id=\"sgb-css-id-167\">\n<p>\u3053\u306e\u30d1\u30bf\u30fc\u30f3\u306f\u3001\u30c7\u30fc\u30bf\u306e\u6574\u7406\u3084\u5206\u985e\u306b\u5f79\u7acb\u3061\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-168\">\n<h3 class=\"wp-block-heading\" id=\"i-47\">6.2 \u4e26\u5217\u51e6\u7406\u3067\u306e\u6ce8\u610f\u70b9\uff1aConcurrentHashMap\u306e\u6d3b\u7528<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-169\">\n<p>\u30de\u30eb\u30c1\u30b9\u30ec\u30c3\u30c9\u74b0\u5883\u3067HashMap\u3092\u4f7f\u7528\u3059\u308b\u5834\u5408\u3001ConcurrentHashMap\u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u304c\u91cd\u8981\u3067\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">Map&lt;String, Integer&gt; concurrentMap = new ConcurrentHashMap&lt;&gt;();\n\n\/\/ \u8907\u6570\u30b9\u30ec\u30c3\u30c9\u304b\u3089\u5b89\u5168\u306b\u64cd\u4f5c\u53ef\u80fd\nconcurrentMap.computeIfAbsent(\"key\", k -&gt; expensiveOperation(k));\n\n\/\/ \u8907\u6570\u306e\u66f4\u65b0\u64cd\u4f5c\u3092\u539f\u5b50\u7684\u306b\u5b9f\u884c\nconcurrentMap.merge(\"counter\", 1, Integer::sum);<\/pre>\n\n\n<div id=\"sgb-css-id-170\">\n<p>ConcurrentHashMap\u306f\u3001\u9ad8\u3044\u4e26\u884c\u6027\u3092\u63d0\u4f9b\u3057\u3064\u3064\u3001\u30c7\u30fc\u30bf\u306e\u4e00\u8cab\u6027\u3092\u4fdd\u8a3c\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-171\">\n<h3 class=\"wp-block-heading\" id=\"i-48\">HashMap\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-172\">\n<p>1.<strong>\u9069\u5207\u306a\u521d\u671f\u5bb9\u91cf\u306e\u8a2d\u5b9a<\/strong><\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">   int expectedSize = 100;\n   Map&lt;String, String&gt; map = new HashMap&lt;&gt;(Math.max((int) (expectedSize \/ 0.75f) + 1, 16));<\/pre>\n\n\n<div id=\"sgb-css-id-173\">\n<p>2.<strong>\u30a4\u30df\u30e5\u30fc\u30bf\u30d6\u30eb\u306a\u30ad\u30fc\u306e\u4f7f\u7528<\/strong><\/p>\n<\/div>\n\n\n<ul class=\"wp-block-list is-style-sango-list-simple\"><div id=\"sgb-css-id-174\">\n<li>String, Integer, Enum\u306a\u3069\u306e\u30a4\u30df\u30e5\u30fc\u30bf\u30d6\u30eb\u306a\u30af\u30e9\u30b9\u3092\u30ad\u30fc\u3068\u3057\u3066\u4f7f\u7528\u3059\u308b<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-175\">\n<li>\u30ab\u30b9\u30bf\u30e0\u30af\u30e9\u30b9\u3092\u30ad\u30fc\u3068\u3059\u308b\u5834\u5408\u306f\u3001\u30a4\u30df\u30e5\u30fc\u30bf\u30d6\u30eb\u306b\u3059\u308b<\/li>\n<\/div><\/ul>\n\n\n<div id=\"sgb-css-id-176\">\n<p>3.<strong>null\u30ad\u30fc\u3068\u5024\u306e\u6271\u3044<\/strong><\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">   map.put(null, \"Value for null key\"); \/\/ \u8a31\u5bb9\u3055\u308c\u308b\u304c\u3001\u907f\u3051\u308b\u3079\u304d\n   map.put(\"Key\", null); \/\/ \u5024\u3068\u3057\u3066\u306enull\u306f\u4e00\u822c\u7684\u306b\u554f\u984c\u306a\u3044<\/pre>\n\n\n<div id=\"sgb-css-id-177\">\n<p>4.<strong>\u30ab\u30b9\u30bf\u30e0\u30af\u30e9\u30b9\u3092\u30ad\u30fc\u3068\u3059\u308b\u5834\u5408\u306ehashCode()\u3068equals()\u306e\u9069\u5207\u306a\u5b9f\u88c5<\/strong><\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">   public class CustomKey {\n       private final String id;\n       private final int value;\n\n       \/\/ \u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u3001\u30b2\u30c3\u30bf\u30fc\u306f\u7701\u7565\n\n       @Override\n       public int hashCode() {\n           return Objects.hash(id, value);\n       }\n\n       @Override\n       public boolean equals(Object obj) {\n           if (this == obj) return true;\n           if (!(obj instanceof CustomKey)) return false;\n           CustomKey other = (CustomKey) obj;\n           return Objects.equals(id, other.id) &amp;&amp; value == other.value;\n       }\n   }<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-49\">\u4e00\u822c\u7684\u306a\u843d\u3068\u3057\u7a74\u3068\u56de\u907f\u65b9\u6cd5<\/h3>\n\n\n\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">1. <strong>\u30ad\u30fc\u306e\u53ef\u5909\u6027\u306b\u3088\u308b\u554f\u984c<\/strong><\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ul class=\"wp-block-list\"><div id=\"sgb-css-id-178\">\n<li>\u30df\u30e5\u30fc\u30bf\u30d6\u30eb\u306a\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u30ad\u30fc\u3068\u3057\u3066\u4f7f\u7528\u3059\u308b\u3068\u3001\u30cf\u30c3\u30b7\u30e5\u30b3\u30fc\u30c9\u304c\u5909\u66f4\u3055\u308c\u3001\u8981\u7d20\u304c\u898b\u3064\u304b\u3089\u306a\u304f\u306a\u308b\u53ef\u80fd\u6027\u304c\u3042\u308a\u307e\u3059\u3002<\/li>\n<\/div>\n\n\n<li>\u89e3\u6c7a\u7b56\uff1a\u30a4\u30df\u30e5\u30fc\u30bf\u30d6\u30eb\u306a\u30ad\u30fc\u3092\u4f7f\u7528\u3059\u308b\u304b\u3001\u30ad\u30fc\u306e\u30df\u30e5\u30fc\u30bf\u30d6\u30eb\u306a\u90e8\u5206\u3092\u30cf\u30c3\u30b7\u30e5\u30b3\u30fc\u30c9\u8a08\u7b97\u306b\u4f7f\u7528\u3057\u306a\u3044\u3002<\/li>\n<\/ul>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">2.<strong>\u30cf\u30c3\u30b7\u30e5\u30b3\u30fc\u30c9\u306e\u4e0d\u9069\u5207\u306a\u5b9f\u88c5<\/strong><\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ul class=\"wp-block-list\"><div id=\"sgb-css-id-179\">\n<li>\u3059\u3079\u3066\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u304c\u540c\u3058\u30cf\u30c3\u30b7\u30e5\u30b3\u30fc\u30c9\u3092\u8fd4\u3059\u3068\u3001HashMap\u306e\u6027\u80fd\u304c\u4f4e\u4e0b\u3057\u307e\u3059\u3002<\/li>\n<\/div>\n\n\n<li>\u89e3\u6c7a\u7b56\uff1a\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u91cd\u8981\u306a\u30d5\u30a3\u30fc\u30eb\u30c9\u3092\u4f7f\u7528\u3057\u3066\u3001\u9069\u5207\u306b\u5206\u6563\u3055\u308c\u305f\u30cf\u30c3\u30b7\u30e5\u30b3\u30fc\u30c9\u3092\u5b9f\u88c5\u3059\u308b\u3002<\/li>\n<\/ul>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">3.<strong>\u5927\u91cf\u306e\u30c7\u30fc\u30bf\u3092\u6271\u3046\u969b\u306e\u30e1\u30e2\u30ea\u7ba1\u7406<\/strong><\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ul class=\"wp-block-list\"><div id=\"sgb-css-id-180\">\n<li>\u975e\u5e38\u306b\u5927\u304d\u306aHashMap\u306f\u30e1\u30e2\u30ea\u3092\u5727\u8feb\u3059\u308b\u53ef\u80fd\u6027\u304c\u3042\u308a\u307e\u3059\u3002<\/li>\n<\/div>\n\n\n<li>\u89e3\u6c7a\u7b56\uff1a\u5fc5\u8981\u306b\u5fdc\u3058\u3066\u30c7\u30fc\u30bf\u3092\u30c7\u30a3\u30b9\u30af\u306b\u4fdd\u5b58\u3059\u308b\u304b\u3001\u30ad\u30e3\u30c3\u30b7\u30e5\u6226\u7565\uff08\u4f8b\uff1aLRU\uff09\u3092\u5b9f\u88c5\u3059\u308b\u3002<\/li>\n<\/ul>\n<\/div><\/div>\n\n\n<div id=\"sgb-css-id-181\">\n<h3 class=\"wp-block-heading\" id=\"i-50\">\u5b9f\u969b\u306e\u30d7\u30ed\u30b8\u30a7\u30af\u30c8\u3067\u306e\u4f7f\u7528\u4f8b<\/h3>\n<\/div>\n\n\n<ol class=\"wp-block-list is-style-sango-list-simple\">\n<li><strong>Spring Framework\u306eBeanFactory\u5b9f\u88c5<\/strong>\n<ul class=\"wp-block-list is-style-sango-list-simple\">\n<li>Spring IoC\uff08Inversion of Control\uff09\u30b3\u30f3\u30c6\u30ca\u306fHashMap\u3092\u4f7f\u7528\u3057\u3066bean\u306e\u5b9a\u7fa9\u3092\u7ba1\u7406\u3057\u3066\u3044\u307e\u3059\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Guava\u30e9\u30a4\u30d6\u30e9\u30ea\u306eCache\u5b9f\u88c5<\/strong>\n<ul class=\"wp-block-list is-style-sango-list-simple\"><div id=\"sgb-css-id-182\">\n<li>Google\u306eGuava\u30e9\u30a4\u30d6\u30e9\u30ea\u306f\u3001HashMap\u3092\u30d9\u30fc\u30b9\u306b\u3057\u305f\u9ad8\u5ea6\u306a\u30ad\u30e3\u30c3\u30b7\u30e5\u6a5f\u80fd\u3092\u63d0\u4f9b\u3057\u3066\u3044\u307e\u3059\u3002<\/li>\n<\/div><\/ul>\n<\/li>\n<\/ol>\n\n\n<div id=\"sgb-css-id-183\">\n<p>HashMap\u3092\u52b9\u679c\u7684\u306b\u4f7f\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u591a\u304f\u306e\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u30bf\u30b9\u30af\u3092\u52b9\u7387\u7684\u306b\u89e3\u6c7a\u3067\u304d\u307e\u3059\u3002\u3053\u308c\u3089\u306e\u30d1\u30bf\u30fc\u30f3\u3068\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\u3092\u9069\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u3088\u308a\u5805\u7262\u3067\u52b9\u7387\u7684\u306aJava\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3092\u958b\u767a\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u308b\u3067\u3057\u3087\u3046\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-184\">\n<h2 class=\"wp-block-heading\" id=\"i-51\">7. Java 8\u4ee5\u964d\u306eHashMap\uff1a\u65b0\u6a5f\u80fd\u3068\u6539\u5584\u70b9<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-185\">\n<p>Java 8\u4ee5\u964d\u3001HashMap\u306b\u306f\u591a\u304f\u306e\u65b0\u6a5f\u80fd\u3068\u6539\u5584\u304c\u52a0\u3048\u3089\u308c\u307e\u3057\u305f\u3002\u3053\u308c\u3089\u306e\u5909\u66f4\u306f\u3001\u30b3\u30fc\u30c9\u306e\u53ef\u8aad\u6027\u5411\u4e0a\u3068\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u306e\u6700\u9069\u5316\u3092\u76ee\u7684\u3068\u3057\u3066\u3044\u307e\u3059\u3002\u3053\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u4e3b\u8981\u306a\u65b0\u6a5f\u80fd\u3068\u305d\u306e\u6d3b\u7528\u65b9\u6cd5\u306b\u3064\u3044\u3066\u89e3\u8aac\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-186\">\n<h3 class=\"wp-block-heading\" id=\"i-52\">7.1 computeIfAbsent()\u3068merge()\uff1a\u6761\u4ef6\u4ed8\u304d\u64cd\u4f5c\u306e\u7c21\u7565\u5316<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-187\">\n<h4 class=\"wp-block-heading\" id=\"i-53\">computeIfAbsent()<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-188\">\n<p>\u3053\u306e\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u30ad\u30fc\u304c\u5b58\u5728\u3057\u306a\u3044\u5834\u5408\u306b\u306e\u307f\u5024\u3092\u8a08\u7b97\u3057\u3066\u8ffd\u52a0\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/\/ \u5f93\u6765\u306e\u65b9\u6cd5\nif (!map.containsKey(key)) {\n    map.put(key, expensiveOperation(key));\n}\n\n\/\/ Java 8\u4ee5\u964d\nmap.computeIfAbsent(key, k -&gt; expensiveOperation(k));<\/pre>\n\n\n<div id=\"sgb-css-id-189\">\n<p>\u3053\u306e\u30e1\u30bd\u30c3\u30c9\u306f\u7279\u306b\u3001\u30de\u30c3\u30d7\u5185\u306e\u30de\u30c3\u30d7\u3084\u30ea\u30b9\u30c8\u3092\u6271\u3046\u969b\u306b\u975e\u5e38\u306b\u6709\u7528\u3067\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">Map&lt;String, List&lt;String&gt;&gt; multimap = new HashMap&lt;&gt;();\nmultimap.computeIfAbsent(\"fruits\", k -&gt; new ArrayList&lt;&gt;()).add(\"apple\");<\/pre>\n\n\n<div id=\"sgb-css-id-190\">\n<h4 class=\"wp-block-heading\" id=\"i-54\">merge()<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-191\">\n<p>merge()\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u30ad\u30fc\u306e\u5b58\u5728\u6709\u7121\u306b\u95a2\u308f\u3089\u305a\u3001\u6307\u5b9a\u3055\u308c\u305f\u65b9\u6cd5\u3067\u5024\u3092\u7d50\u5408\u307e\u305f\u306f\u8ffd\u52a0\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/\/ \u5f93\u6765\u306e\u65b9\u6cd5\nif (map.containsKey(key)) {\n    map.put(key, map.get(key) + value);\n} else {\n    map.put(key, value);\n}\n\n\/\/ Java 8\u4ee5\u964d\nmap.merge(key, value, (oldValue, newValue) -&gt; oldValue + newValue);<\/pre>\n\n\n<div id=\"sgb-css-id-192\">\n<p>\u3053\u306e\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u30ab\u30a6\u30f3\u30c6\u30a3\u30f3\u30b0\u3084\u5024\u306e\u7d2f\u7a4d\u306b\u7279\u306b\u4fbf\u5229\u3067\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">Map&lt;String, Integer&gt; wordCount = new HashMap&lt;&gt;();\nString[] words = {\"apple\", \"banana\", \"apple\", \"cherry\"};\nfor (String word : words) {\n    wordCount.merge(word, 1, Integer::sum);\n}<\/pre>\n\n\n<div id=\"sgb-css-id-193\">\n<h3 class=\"wp-block-heading\" id=\"i-55\">7.2 forEach()\u3068replaceAll()\uff1a\u30e9\u30e0\u30c0\u5f0f\u3092\u6d3b\u7528\u3057\u305f\u52b9\u7387\u7684\u306a\u51e6\u7406<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-194\">\n<h4 class=\"wp-block-heading\" id=\"i-56\">forEach()<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-195\">\n<p>forEach()\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u7528\u3059\u308b\u3068\u3001\u30de\u30c3\u30d7\u306e\u5404\u30a8\u30f3\u30c8\u30ea\u306b\u5bfe\u3057\u3066\u7c21\u6f54\u306b\u64cd\u4f5c\u3092\u884c\u3048\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">Map&lt;String, Integer&gt; scores = new HashMap&lt;&gt;();\nscores.put(\"Alice\", 95);\nscores.put(\"Bob\", 80);\n\n\/\/ Java 8\u4ee5\u964d\nscores.forEach((name, score) -&gt; System.out.println(name + \" scored \" + score));<\/pre>\n\n\n<div id=\"sgb-css-id-196\">\n<h4 class=\"wp-block-heading\" id=\"i-57\">replaceAll()<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-197\">\n<p>replaceAll()\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u30de\u30c3\u30d7\u306e\u5168\u3066\u306e\u5024\u3092\u5909\u63db\u3059\u308b\u969b\u306b\u4fbf\u5229\u3067\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">Map&lt;String, Integer&gt; prices = new HashMap&lt;&gt;();\nprices.put(\"apple\", 100);\nprices.put(\"banana\", 80);\n\n\/\/ \u5168\u3066\u306e\u4fa1\u683c\u309220%\u5f15\u304d\u306b\u3059\u308b\nprices.replaceAll((k, v) -&gt; (int)(v * 0.8));<\/pre>\n\n\n<div id=\"sgb-css-id-198\">\n<h3 class=\"wp-block-heading\" id=\"i-58\">\u5185\u90e8\u5b9f\u88c5\u306e\u6539\u5584<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-199\">\n<p>Java 8\u3067\u306f\u3001HashMap\u306e\u5185\u90e8\u5b9f\u88c5\u3082\u6539\u5584\u3055\u308c\u307e\u3057\u305f\u3002\u7279\u306b\u6ce8\u76ee\u3059\u3079\u304d\u70b9\u306f\u3001\u30d0\u30b1\u30c3\u30c8\u30b5\u30a4\u30ba\u304c8\u3092\u8d85\u3048\u305f\u5834\u5408\u306b\u3001\u30ea\u30f3\u30af\u30c9\u30ea\u30b9\u30c8\u304b\u3089\u8d64\u9ed2\u6728\u306b\u5909\u63db\u3055\u308c\u308b\u6a5f\u80fd\u3067\u3059\u3002\u3053\u306e\u6539\u5584\u306b\u3088\u308a\u3001\u30cf\u30c3\u30b7\u30e5\u885d\u7a81\u304c\u591a\u3044\u5834\u5408\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u304c\u5927\u5e45\u306b\u5411\u4e0a\u3057\u307e\u3057\u305f\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-200\">\n<h3 class=\"wp-block-heading\" id=\"i-59\">Java 9\u4ee5\u964d\u306e\u8ffd\u52a0\u6539\u5584\u70b9<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-201\">\n<p>Java 9\u3067\u306f\u3001Map\u306e\u4f5c\u6210\u3092\u3055\u3089\u306b\u7c21\u7565\u5316\u3059\u308b\u30d5\u30a1\u30af\u30c8\u30ea\u30e1\u30bd\u30c3\u30c9\u304c\u5c0e\u5165\u3055\u308c\u307e\u3057\u305f\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/\/ \u4e0d\u5909Map\u306e\u4f5c\u6210\nMap&lt;String, Integer&gt; immutableMap = Map.of(\"one\", 1, \"two\", 2, \"three\", 3);\n\n\/\/ \u8981\u7d20\u6570\u304c\u591a\u3044\u5834\u5408\nMap&lt;String, Integer&gt; largeMap = Map.ofEntries(\n    Map.entry(\"one\", 1),\n    Map.entry(\"two\", 2),\n    \/\/ ... \u6700\u592710\u500b\u307e\u3067\n);<\/pre>\n\n\n<div id=\"sgb-css-id-202\">\n<h3 class=\"wp-block-heading\" id=\"i-60\">\u65b0\u6a5f\u80fd\u6d3b\u7528\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/h3>\n<\/div>\n\n\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">\u65b0\u6a5f\u80fd\u6d3b\u7528\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ol class=\"wp-block-list\"><div id=\"sgb-css-id-203\">\n<li><strong>\u9069\u5207\u306a\u30e1\u30bd\u30c3\u30c9\u306e\u9078\u629e<\/strong>\uff1a \u72b6\u6cc1\u306b\u5fdc\u3058\u3066\u6700\u9069\u306a\u30e1\u30bd\u30c3\u30c9\uff08compute\u7cfb\u3001merge\u3001forEach\u7b49\uff09\u3092\u9078\u629e\u3059\u308b<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-204\">\n<li><strong>\u30e9\u30e0\u30c0\u5f0f\u306e\u52b9\u679c\u7684\u306a\u4f7f\u7528<\/strong>\uff1a \u7c21\u6f54\u3067\u8aad\u307f\u3084\u3059\u3044\u30b3\u30fc\u30c9\u3092\u5fc3\u304c\u3051\u308b<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-205\">\n<li><strong>\u4e0d\u5909Map\u30d5\u30a1\u30af\u30c8\u30ea\u30e1\u30bd\u30c3\u30c9\u306e\u6d3b\u7528<\/strong>\uff1a \u5c0f\u3055\u306a\u4e0d\u5909Map\u304c\u5fc5\u8981\u306a\u5834\u5408\u306fMap.of()\u3092\u4f7f\u7528\u3059\u308b<\/li>\n<\/div>\n\n\n<li><strong>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u610f\u8b58\u3059\u308b<\/strong>\uff1a \u65b0\u30e1\u30bd\u30c3\u30c9\u306f\u4fbf\u5229\u3067\u3059\u304c\u3001\u904e\u5ea6\u306e\u4f7f\u7528\u306f\u907f\u3051\u308b<\/li>\n<\/ol>\n<\/div><\/div>\n\n\n<div id=\"sgb-css-id-206\">\n<h3 class=\"wp-block-heading\" id=\"i-61\">\u307e\u3068\u3081<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-207\">\n<p>Java 8\u4ee5\u964d\u306eHashMap\u306e\u65b0\u6a5f\u80fd\u306f\u3001\u30b3\u30fc\u30c9\u306e\u53ef\u8aad\u6027\u3068\u4fdd\u5b88\u6027\u3092\u5927\u5e45\u306b\u5411\u4e0a\u3055\u305b\u307e\u3059\u3002\u540c\u6642\u306b\u3001\u5185\u90e8\u5b9f\u88c5\u306e\u6539\u5584\u306b\u3088\u308a\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3082\u6700\u9069\u5316\u3055\u308c\u3066\u3044\u307e\u3059\u3002\u3053\u308c\u3089\u306e\u65b0\u6a5f\u80fd\u3092\u9069\u5207\u306b\u6d3b\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u3088\u308a\u52b9\u7387\u7684\u3067\u6d17\u7df4\u3055\u308c\u305fJava\u30b3\u30fc\u30c9\u3092\u66f8\u304f\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-208\">\n<h2 class=\"wp-block-heading\" id=\"i-62\">8. HashMap\u3092\u30de\u30b9\u30bf\u30fc\u3059\u308b\u305f\u3081\u306e\u6b21\u306e\u30b9\u30c6\u30c3\u30d7<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-209\">\n<p>HashMap\u306e\u57fa\u672c\u6982\u5ff5\u304b\u3089\u9ad8\u5ea6\u306a\u4f7f\u7528\u65b9\u6cd5\u307e\u3067\u5b66\u3093\u3067\u304d\u307e\u3057\u305f\u304c\u3001\u771f\u306e\u719f\u7df4\u306b\u306f\u7d99\u7d9a\u7684\u306a\u5b66\u7fd2\u3068\u5b9f\u8df5\u304c\u4e0d\u53ef\u6b20\u3067\u3059\u3002\u3053\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001HashMap\u306e\u30b9\u30ad\u30eb\u3092\u66f4\u306b\u5411\u4e0a\u3055\u305b\u3001Java\u30c7\u30d9\u30ed\u30c3\u30d1\u30fc\u3068\u3057\u3066\u306e\u7dcf\u5408\u7684\u306a\u80fd\u529b\u3092\u9ad8\u3081\u308b\u305f\u3081\u306e\u6b21\u306e\u30b9\u30c6\u30c3\u30d7\u3092\u63d0\u6848\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-210\">\n<h3 class=\"wp-block-heading\" id=\"i-63\">8.1 \u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6e2c\u5b9a\uff1a\u81ea\u4f5c\u306e\u30d9\u30f3\u30c1\u30de\u30fc\u30af\u30c6\u30b9\u30c8<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-211\">\n<p>HashMap\u306e\u6027\u80fd\u3092\u6df1\u304f\u7406\u89e3\u3059\u308b\u306b\u306f\u3001\u69d8\u3005\u306a\u72b6\u6cc1\u4e0b\u3067\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u6e2c\u5b9a\u3059\u308b\u3053\u3068\u304c\u91cd\u8981\u3067\u3059\u3002JMH (Java Microbenchmark Harness) \u3092\u4f7f\u7528\u3057\u3066\u3001\u81ea\u4f5c\u306e\u30d9\u30f3\u30c1\u30de\u30fc\u30af\u30c6\u30b9\u30c8\u3092\u4f5c\u6210\u3057\u3066\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">import org.openjdk.jmh.annotations.*;\n\n@State(Scope.Thread)\n@BenchmarkMode(Mode.AverageTime)\npublic class HashMapBenchmark {\n\n    @Benchmark\n    public void testPut() {\n        Map&lt;String, Integer&gt; map = new HashMap&lt;&gt;();\n        for (int i = 0; i &lt; 1000; i++) {\n            map.put(\"Key\" + i, i);\n        }\n    }\n\n    @Benchmark\n    public void testGet() {\n        Map&lt;String, Integer&gt; map = new HashMap&lt;&gt;();\n        for (int i = 0; i &lt; 1000; i++) {\n            map.put(\"Key\" + i, i);\n        }\n        for (int i = 0; i &lt; 1000; i++) {\n            map.get(\"Key\" + i);\n        }\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-212\">\n<p>\u3053\u306e\u3088\u3046\u306a\u30d9\u30f3\u30c1\u30de\u30fc\u30af\u3092\u4f5c\u6210\u3057\u3001\u7570\u306a\u308b\u30b5\u30a4\u30ba\u306e\u30c7\u30fc\u30bf\u30bb\u30c3\u30c8\u3084\u69d8\u3005\u306a\u64cd\u4f5c\u30d1\u30bf\u30fc\u30f3\u3067\u30c6\u30b9\u30c8\u3059\u308b\u3053\u3068\u3067\u3001HashMap\u306e\u52d5\u4f5c\u3092\u3088\u308a\u6df1\u304f\u7406\u89e3\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-213\">\n<h3 class=\"wp-block-heading\" id=\"i-64\">8.2 \u5b9f\u52d9\u3067\u306e\u6d3b\u7528\uff1a\u30ea\u30a2\u30eb\u30ef\u30fc\u30eb\u30c9\u306e\u4f7f\u7528\u4f8b\u3068\u6ce8\u610f\u70b9<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-214\">\n<p>HashMap\u306e\u5b9f\u52d9\u3067\u306e\u6d3b\u7528\u4f8b\u3092\u5b66\u3073\u3001\u5b9f\u8df5\u3059\u308b\u3053\u3068\u3067\u3001\u7406\u8ad6\u7684\u306a\u77e5\u8b58\u3092\u5b9f\u7528\u7684\u306a\u30b9\u30ad\u30eb\u306b\u5909\u63db\u3067\u304d\u307e\u3059\u3002\u4ee5\u4e0b\u306f\u3001\u3088\u304f\u3042\u308b\u4f7f\u7528\u4f8b\u3068\u305d\u306e\u969b\u306e\u6ce8\u610f\u70b9\u3067\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-215\">\n<p>1.<strong>\u30ad\u30e3\u30c3\u30b7\u30e5\u30b7\u30b9\u30c6\u30e0\u306e\u5b9f\u88c5<\/strong><\/p>\n<\/div>\n\n\n<ul class=\"wp-block-list is-style-sango-list-simple\"><div id=\"sgb-css-id-216\">\n<li>\u6ce8\u610f\u70b9\uff1a\u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u306e\u76e3\u8996\u3001\u30a8\u30f3\u30c8\u30ea\u306e\u6709\u52b9\u671f\u9650\u7ba1\u7406<\/li>\n<\/div><\/ul>\n\n\n<div id=\"sgb-css-id-217\">\n<p>2.<strong>\u30b0\u30e9\u30d5\u30a2\u30eb\u30b4\u30ea\u30ba\u30e0\u3067\u306eHashMap\u306e\u4f7f\u7528<\/strong><\/p>\n<\/div>\n\n\n<ul class=\"wp-block-list is-style-sango-list-simple\"><div id=\"sgb-css-id-218\">\n<li>\u4f8b\uff1a\u96a3\u63a5\u30ea\u30b9\u30c8\u306e\u8868\u73fe\u3001\u8a2a\u554f\u6e08\u307f\u30ce\u30fc\u30c9\u306e\u8ffd\u8de1<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-219\">\n<li>\u6ce8\u610f\u70b9\uff1a\u5927\u898f\u6a21\u30b0\u30e9\u30d5\u3067\u306e\u30e1\u30e2\u30ea\u6d88\u8cbb<\/li>\n<\/div><\/ul>\n\n\n<div id=\"sgb-css-id-220\">\n<p>3.<strong>\u5927\u898f\u6a21\u30c7\u30fc\u30bf\u51e6\u7406\u3067\u306e\u6700\u9069\u5316<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-223\">\n<ul class=\"wp-block-list is-style-sango-list-simple\"><div id=\"sgb-css-id-221\">\n<li>\u6280\u8853\uff1a\u30b7\u30e3\u30fc\u30c7\u30a3\u30f3\u30b0\u3001\u5916\u90e8\u30cf\u30c3\u30b7\u30e5\u30c6\u30fc\u30d6\u30eb\u306e\u4f7f\u7528<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-222\">\n<li>\u6ce8\u610f\u70b9\uff1a\u30c7\u30fc\u30bf\u306e\u504f\u308a\u306b\u3088\u308b\u6027\u80fd\u4f4e\u4e0b\u306e\u56de\u907f<\/li>\n<\/div><\/ul>\n<\/div>\n\n<div id=\"sgb-css-id-224\">\n<p>\u3053\u308c\u3089\u306e\u4f7f\u7528\u4f8b\u3092\u81ea\u8eab\u306e\u30d7\u30ed\u30b8\u30a7\u30af\u30c8\u306b\u9069\u7528\u3057\u3001\u5b9f\u8df5\u7684\u306a\u7d4c\u9a13\u3092\u7a4d\u3080\u3053\u3068\u304c\u91cd\u8981\u3067\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-225\">\n<h3 class=\"wp-block-heading\" id=\"i-65\">\u6b21\u306e\u30b9\u30c6\u30c3\u30d7\uff1a\u3055\u3089\u306a\u308b\u5b66\u7fd2\u3068\u63a2\u6c42<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-226\">\n<p>1.<strong>\u9ad8\u5ea6\u306a\u30c7\u30fc\u30bf\u69cb\u9020\u3068\u30a2\u30eb\u30b4\u30ea\u30ba\u30e0\u306e\u5b66\u7fd2<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-227\">\n<p>   \u30fbConcurrentHashMap, LinkedHashMap, TreeMap\u306e\u5185\u90e8\u5b9f\u88c5\u306e\u7406\u89e3<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-228\">\n<p>   \u30fbGuava\u30e9\u30a4\u30d6\u30e9\u30ea\u306e MultiMap, BiMap \u306e\u6d3b\u7528<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-229\">\n<p>2.<strong><strong>\u4e26\u884c\u51e6\u7406\u3068\u30b9\u30ec\u30c3\u30c9\u30bb\u30fc\u30d5\u306a\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0<\/strong><\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-230\">\n<p>   \u30fbjava.util.concurrent \u30d1\u30c3\u30b1\u30fc\u30b8\u306e\u6df1\u3044\u7406\u89e3<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-231\">\n<p>   \u30fb\u30ed\u30c3\u30af\u30d5\u30ea\u30fc\u30a2\u30eb\u30b4\u30ea\u30ba\u30e0\u306e\u5b66\u7fd2<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-232\">\n<p>3.<strong><strong>\u30aa\u30fc\u30d7\u30f3\u30bd\u30fc\u30b9\u30d7\u30ed\u30b8\u30a7\u30af\u30c8\u306e\u5206\u6790<\/strong><\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-233\">\n<p>   \u30fbSpring Framework \u3084 Apache Commons Collections \u306e\u30b3\u30fc\u30c9\u30ea\u30fc\u30c7\u30a3\u30f3\u30b0<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-234\">\n<p>   \u30fb\u5927\u898f\u6a21\u30d7\u30ed\u30b8\u30a7\u30af\u30c8\u3067\u306eHashMap\u306e\u4f7f\u7528\u30d1\u30bf\u30fc\u30f3\u306e\u5206\u6790<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-235\">\n<p>4.<strong><strong>Java\u8a8d\u5b9a\u8cc7\u683c\u306e\u53d6\u5f97<\/strong><\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-236\">\n<p>   \u30fbOracle Certified Professional, Java SE 11 Developer \u306e\u53d6\u5f97<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-237\">\n<p>   \u30fb\u5b66\u7fd2\u30ea\u30bd\u30fc\u30b9\uff1a<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-238\">\n<p>       \u30fb\u66f8\u7c4d\uff1a\u300cEffective Java\u300dby Joshua Bloch<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-239\">\n<p>       \u30fb\u30aa\u30f3\u30e9\u30a4\u30f3\u30ea\u30bd\u30fc\u30b9\uff1aBaeldung, Java Code Geeks<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-240\">\n<p>5.<strong><strong>\u6700\u65b0\u306e\u52d5\u5411\u306e\u30d5\u30a9\u30ed\u30fc<\/strong><\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-241\">\n<p>   \u30fbJava \u306e\u65b0\u30d0\u30fc\u30b8\u30e7\u30f3\u3067\u306eHashMap\u306e\u6539\u5584\u70b9\u306e\u78ba\u8a8d<\/p>\n<\/div>\n\n\n<p>   \u30fb\u6280\u8853\u30ab\u30f3\u30d5\u30a1\u30ec\u30f3\u30b9\u3084\u52c9\u5f37\u4f1a\u3078\u306e\u7a4d\u6975\u7684\u306a\u53c2\u52a0<\/p>\n\n\n<div id=\"sgb-css-id-242\">\n<h3 class=\"wp-block-heading\" id=\"i-66\">\u307e\u3068\u3081<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-243\">\n<p>HashMap\u306e\u30de\u30b9\u30bf\u30ea\u30fc\u306f\u3001Java\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u30b9\u30ad\u30eb\u5168\u4f53\u306e\u5411\u4e0a\u306b\u3064\u306a\u304c\u308a\u307e\u3059\u3002\u7406\u8ad6\u7684\u306a\u7406\u89e3\u3001\u5b9f\u8df5\u7684\u306a\u5fdc\u7528\u3001\u305d\u3057\u3066\u6700\u65b0\u6280\u8853\u306e\u30ad\u30e3\u30c3\u30c1\u30a2\u30c3\u30d7\u3092\u7d44\u307f\u5408\u308f\u305b\u308b\u3053\u3068\u3067\u3001\u3088\u308a\u52b9\u7387\u7684\u3067\u4fe1\u983c\u6027\u306e\u9ad8\u3044\u30bd\u30d5\u30c8\u30a6\u30a7\u30a2\u3092\u958b\u767a\u3059\u308b\u80fd\u529b\u3092\u8eab\u306b\u3064\u3051\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<p>\u7d99\u7d9a\u7684\u306a\u5b66\u7fd2\u3068\u5b9f\u8df5\u3092\u901a\u3058\u3066\u3001HashMap\u3092\u5358\u306a\u308b\u30c7\u30fc\u30bf\u69cb\u9020\u3068\u3057\u3066\u3067\u306f\u306a\u304f\u3001\u554f\u984c\u89e3\u6c7a\u306e\u305f\u3081\u306e\u5f37\u529b\u306a\u30c4\u30fc\u30eb\u3068\u3057\u3066\u6d3b\u7528\u3067\u304d\u308b\u3088\u3046\u306b\u306a\u308b\u3067\u3057\u3087\u3046\u3002\u305d\u3057\u3066\u3001\u3053\u306e\u904e\u7a0b\u3067\u5f97\u3089\u308c\u308b\u6df1\u3044\u7406\u89e3\u306f\u3001\u3042\u306a\u305f\u3092\u3088\u308a\u512a\u308c\u305fJava\u30c7\u30d9\u30ed\u30c3\u30d1\u30fc\u3078\u3068\u5c0e\u304f\u3053\u3068\u3067\u3057\u3087\u3046\u3002<\/p>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u3042\u306a\u305f\u306f\u65e5\u3005\u306eJava\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u3067\u3001\u30c7\u30fc\u30bf\u3092\u52b9\u7387\u7684\u306b\u7ba1\u7406\u3057\u3001\u9ad8\u901f\u306b\u30a2\u30af\u30bb\u30b9\u3059\u308b\u65b9\u6cd5\u3092\u63a2\u3057\u3066\u3044\u307e\u305b\u3093\u304b\uff1f\u305d\u3093\u306a\u3042\u306a\u305f\u306b\u3001Java\u306eHashMap\u3092\u30de\u30b9\u30bf\u30fc\u3059\u308b\u6c7a\u5b9a\u7248\u306e\u8a18\u4e8b\u3092\u304a\u5c4a\u3051\u3057\u307e\u3059\u3002 HashMap\u306f\u3001Java\u30d7\u30ed &#8230; <\/p>\n","protected":false},"author":1,"featured_media":3049,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2,66],"tags":[],"class_list":{"0":"post-302","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-java","8":"category-java-syntax"},"_links":{"self":[{"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/posts\/302","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=302"}],"version-history":[{"count":11,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/posts\/302\/revisions"}],"predecessor-version":[{"id":3077,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/posts\/302\/revisions\/3077"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/media\/3049"}],"wp:attachment":[{"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=302"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=302"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=302"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}