{"id":794,"date":"2024-11-18T16:14:12","date_gmt":"2024-11-18T07:14:12","guid":{"rendered":"https:\/\/dexall.co.jp\/articles\/?p=794"},"modified":"2025-03-24T08:52:49","modified_gmt":"2025-03-23T23:52:49","slug":"java%e3%81%aemap%e6%b4%bb%e7%94%a8%e5%ae%8c%e5%85%a8%e3%82%ac%e3%82%a4%e3%83%89%ef%bc%9a%e5%9f%ba%e7%a4%8e%e3%81%8b%e3%82%89%e5%ae%9f%e8%b7%b5%e3%81%be%e3%81%a7%e8%a7%a3%e8%aa%ac%e3%81%99%e3%82%8b7","status":"publish","type":"post","link":"https:\/\/dexall.co.jp\/articles\/?p=794","title":{"rendered":"Java\u306eMap\u6d3b\u7528\u5b8c\u5168\u30ac\u30a4\u30c9\uff1a\u57fa\u790e\u304b\u3089\u5b9f\u8df5\u307e\u3067\u89e3\u8aac\u3059\u308b7\u3064\u306e\u91cd\u8981\u30dd\u30a4\u30f3\u30c8"},"content":{"rendered":"<div id=\"sgb-css-id-1\">\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\">\u306f\u3058\u3081\u306b<\/a>  <\/li>  <li>    <a href=\"#i-1\">\u8a18\u4e8b\u306e\u69cb\u6210<\/a>  <\/li>  <li>    <a href=\"#i-2\">\uff11\uff0eJava\u306e\u9023\u60f3\u914d\u5217\uff08Map\uff09\u3068\u306f\uff1a\u57fa\u790e\u77e5\u8b58\u3068\u7279\u5fb4<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-3\">1.1 \u9023\u60f3\u914d\u5217\u3068Map\u30a4\u30f3\u30bf\u30fc\u30d5\u30a7\u30fc\u30b9\u306e\u95a2\u4fc2\u6027\u3092\u7406\u89e3\u3059\u308b<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-4\">1.2 HashMap\u3092\u4e2d\u5fc3\u3068\u3057\u305fMap\u5b9f\u88c5\u30af\u30e9\u30b9\u306e\u7a2e\u985e\u3068\u7279\u5fb4<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-6\">\uff12\uff0e\u57fa\u672c\u7684\u306a\u4f7f\u3044\u65b9\uff1aMap\u64cd\u4f5c\u306e\u57fa\u790e\u304b\u3089\u5fdc\u7528\u307e\u3067<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-7\">2.1 \u30ad\u30fc\u3068\u5024\u306e\u8ffd\u52a0\u30fb\u53d6\u5f97\u30fb\u66f4\u65b0\u30fb\u524a\u9664\u306e\u57fa\u672c\u64cd\u4f5c<\/a>      <\/li>      <li>        <a href=\"#i-11\">2.2 \u4fbf\u5229\u306a\u30e1\u30bd\u30c3\u30c9\u3092\u6d3b\u7528\u3057\u305f\u30de\u30c3\u30d7\u306e\u64cd\u4f5c\u30c6\u30af\u30cb\u30c3\u30af<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-14\">2.3 Java 8\u4ee5\u964d\u3067\u8ffd\u52a0\u3055\u308c\u305f\u65b0\u3057\u3044Map\u64cd\u4f5c\u30e1\u30bd\u30c3\u30c9<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-17\">\uff13\uff0e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u610f\u8b58\u3057\u305fMap\u5b9f\u88c5\u30af\u30e9\u30b9\u306e\u9078\u3073\u65b9<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-18\">3.1 HashMap\u3068TreeMap\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6bd4\u8f03<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-21\">3.2 \u5927\u91cf\u30c7\u30fc\u30bf\u51e6\u7406\u6642\u306e\u6700\u9069\u306a\u5b9f\u88c5\u30af\u30e9\u30b9\u306e\u9078\u5b9a\u65b9\u6cd5<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-25\">\uff14\uff0e\u5b9f\u8df5\u7684\u306aMap\u6d3b\u7528\u30d1\u30bf\u30fc\u30f3\u3068\u5b9f\u88c5\u4f8b<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-26\">4.1 \u30ad\u30e3\u30c3\u30b7\u30e5\u3068\u3057\u3066\u306eMap\u6d3b\u7528\u65b9\u6cd5<\/a>      <\/li>      <li>        <a href=\"#i-29\">4.2 \u30c7\u30fc\u30bf\u306e\u96c6\u8a08\u30fb\u5206\u6790\u3067\u306eMap\u6d3b\u7528\u30c6\u30af\u30cb\u30c3\u30af<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-32\">4.3 \u8907\u6570\u306eMap\u3092\u7d44\u307f\u5408\u308f\u305b\u305f\u9ad8\u5ea6\u306a\u5b9f\u88c5\u30d1\u30bf\u30fc\u30f3<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-35\">\uff15\uff0eMap\u3092\u4f7f\u7528\u3059\u308b\u969b\u306e\u6ce8\u610f\u70b9\u3068\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-36\">5.1 Null\u30dd\u30a4\u30f3\u30bf\u3084ConcurrentModificationException\u306e\u56de\u907f\u65b9\u6cd5<\/a>      <\/li>      <li>        <a href=\"#i-39\">5.2 \u30b9\u30ec\u30c3\u30c9\u30bb\u30fc\u30d5\u306a\u5b9f\u88c5\u306e\u305f\u3081\u306e\u30dd\u30a4\u30f3\u30c8<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-42\">5.3 \u30e1\u30e2\u30ea\u52b9\u7387\u3092\u8003\u616e\u3057\u305fMap\u5b9f\u88c5\u306e\u30b3\u30c4<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-45\">\uff16\uff0e\u3088\u304f\u3042\u308b\u30d0\u30b0\u3068\u5bfe\u51e6\u6cd5\uff1a\u30c8\u30e9\u30d6\u30eb\u30b7\u30e5\u30fc\u30c6\u30a3\u30f3\u30b0\u30ac\u30a4\u30c9<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-46\">6.1 \u30ad\u30fc\u306e\u91cd\u8907\u3084\u60f3\u5b9a\u5916\u306e\u4e0a\u66f8\u304d\u3078\u306e\u5bfe\u51e6<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-49\">6.2 \u30e1\u30e2\u30ea\u30ea\u30fc\u30af\u3092\u9632\u3050\u305f\u3081\u306e\u5b9f\u88c5\u65b9\u6cd5<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-52\">\uff17\uff0e\u767a\u5c55\u7684\u306a\u30c8\u30d4\u30c3\u30af\uff1aMap\u306e\u9ad8\u5ea6\u306a\u4f7f\u3044\u65b9<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-53\">7.1 \u30ab\u30b9\u30bf\u30e0\u30ad\u30fc\u30af\u30e9\u30b9\u306e\u5b9f\u88c5\u65b9\u6cd5\u3068\u30dd\u30a4\u30f3\u30c8<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-56\">7.2 Java 9\u4ee5\u964d\u306e\u65b0\u6a5f\u80fd\u3068Map\u306e\u9032\u5316<\/a>      <\/li>    <\/ul>  <\/li>  <li class=\"last\">    <a href=\"#i-60\">\u307e\u3068\u3081\uff1a\u52b9\u679c\u7684\u306aMap\u6d3b\u7528\u306e\u305f\u3081\u306b\u62bc\u3055\u3048\u308b\u3079\u304d\u30dd\u30a4\u30f3\u30c8<\/a>  <\/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\">\u306f\u3058\u3081\u306b<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-2\">\n<p>\u9023\u60f3\u914d\u5217\uff08Map\uff09\u306f\u3001Java\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u306b\u304a\u3051\u308b\u6700\u3082\u91cd\u8981\u306a\u30c7\u30fc\u30bf\u69cb\u9020\u306e1\u3064\u3067\u3059\u3002\u30ad\u30fc\u3068\u5024\u306e\u30da\u30a2\u3067\u30c7\u30fc\u30bf\u3092\u7ba1\u7406\u3067\u304d\u308b\u67d4\u8edf\u306a\u4ed5\u7d44\u307f\u3092\u63d0\u4f9b\u3057\u3001\u591a\u304f\u306e\u5b9f\u8df5\u7684\u306a\u30b7\u30fc\u30f3\u3067\u6d3b\u7528\u3055\u308c\u3066\u3044\u307e\u3059\u3002\u3057\u304b\u3057\u3001\u305d\u306e\u8c4a\u5bcc\u306a\u6a5f\u80fd\u3068\u5b9f\u88c5\u306e\u9078\u629e\u80a2\u306e\u591a\u3055\u3086\u3048\u306b\u3001\u52b9\u7387\u7684\u306a\u6d3b\u7528\u65b9\u6cd5\u3092\u7406\u89e3\u3059\u308b\u3053\u3068\u306b\u8ab2\u984c\u3092\u611f\u3058\u3066\u3044\u308b\u958b\u767a\u8005\u3082\u5c11\u306a\u304f\u3042\u308a\u307e\u305b\u3093\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-3\">\n<p>\u3053\u306e\u8a18\u4e8b\u3067\u306f\u3001Java\u306e\u9023\u60f3\u914d\u5217\uff08Map\uff09\u306b\u3064\u3044\u3066\u3001\u57fa\u790e\u7684\u306a\u4f7f\u3044\u65b9\u304b\u3089\u5b9f\u8df5\u7684\u306a\u6d3b\u7528\u65b9\u6cd5\u3001\u3055\u3089\u306b\u306f\u6700\u65b0\u306eJava\u30d0\u30fc\u30b8\u30e7\u30f3\u3067\u8ffd\u52a0\u3055\u308c\u305f\u6a5f\u80fd\u307e\u3067\u3001\u4f53\u7cfb\u7684\u306b\u89e3\u8aac\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-4\">\n<h2 class=\"wp-block-heading\" id=\"i-1\">\u8a18\u4e8b\u306e\u69cb\u6210<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-5\">\n<p>\u672c\u8a18\u4e8b\u306f\u3001\u4ee5\u4e0b\u306e7\u3064\u306e\u91cd\u8981\u306a\u30dd\u30a4\u30f3\u30c8\u306b\u7126\u70b9\u3092\u5f53\u3066\u3066\u89e3\u8aac\u3092\u9032\u3081\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-12\">\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<ol class=\"wp-block-list\"><div id=\"sgb-css-id-6\">\n<li><strong>\u57fa\u790e\u77e5\u8b58\u3068\u7279\u5fb4<\/strong>\uff1a Map\u30a4\u30f3\u30bf\u30fc\u30d5\u30a7\u30fc\u30b9\u306e\u57fa\u672c\u6982\u5ff5\u3068\u7279\u5fb4<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-7\">\n<li><strong>\u57fa\u672c\u7684\u306a\u4f7f\u3044\u65b9<\/strong>\uff1a \u65e5\u5e38\u7684\u306aMap\u64cd\u4f5c\u306e\u57fa\u790e\u304b\u3089\u5fdc\u7528<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-8\">\n<li><strong>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316<\/strong>\uff1a \u9069\u5207\u306a\u5b9f\u88c5\u30af\u30e9\u30b9\u306e\u9078\u629e\u65b9\u6cd5<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-9\">\n<li><strong>\u5b9f\u8df5\u7684\u306a\u6d3b\u7528\u30d1\u30bf\u30fc\u30f3<\/strong>\uff1a \u5177\u4f53\u7684\u306a\u5b9f\u88c5\u4f8b\u306e\u7d39\u4ecb<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-10\">\n<li><strong>\u6ce8\u610f\u70b9\u3068\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/strong>\uff1a \u52b9\u7387\u7684\u3067\u5b89\u5168\u306a\u5b9f\u88c5\u306e\u30dd\u30a4\u30f3\u30c8<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-11\">\n<li><strong>\u30c8\u30e9\u30d6\u30eb\u30b7\u30e5\u30fc\u30c6\u30a3\u30f3\u30b0<\/strong>\uff1a \u3088\u304f\u3042\u308b\u30d0\u30b0\u3068\u5bfe\u51e6\u6cd5<\/li>\n<\/div>\n\n\n<li><strong>\u767a\u5c55\u7684\u306a\u30c8\u30d4\u30c3\u30af<\/strong>\uff1a \u6700\u65b0\u6a5f\u80fd\u3068\u9ad8\u5ea6\u306a\u4f7f\u3044\u65b9<\/li>\n<\/ol>\n<\/div><\/div>\n<\/div>\n\n<div id=\"sgb-css-id-13\">\n<p>\u5404\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u7406\u8ad6\u7684\u306a\u89e3\u8aac\u3060\u3051\u3067\u306a\u304f\u3001\u5b9f\u8df5\u7684\u306a\u30b3\u30fc\u30c9\u4f8b\u3092\u4ea4\u3048\u306a\u304c\u3089\u3001\u73fe\u5834\u3067\u5373\u5ea7\u306b\u6d3b\u7528\u3067\u304d\u308b\u77e5\u8b58\u3092\u63d0\u4f9b\u3057\u3066\u3044\u304d\u307e\u3059\u3002\u521d\u7d1a\u8005\u304b\u3089\u4e2d\u7d1a\u8005\u307e\u3067\u3001\u5e45\u5e83\u3044\u958b\u767a\u8005\u306e\u65b9\u3005\u306e\u6280\u8853\u529b\u5411\u4e0a\u306b\u8ca2\u732e\u3067\u304d\u308b\u5185\u5bb9\u3068\u306a\u3063\u3066\u3044\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-14\">\n<p>\u305d\u308c\u3067\u306f\u3001Map\u306e\u57fa\u672c\u6982\u5ff5\u304b\u3089\u9806\u306b\u898b\u3066\u3044\u304d\u307e\u3057\u3087\u3046\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-15\">\n<h2 class=\"wp-block-heading\" id=\"i-2\">\uff11\uff0eJava\u306e\u9023\u60f3\u914d\u5217\uff08Map\uff09\u3068\u306f\uff1a\u57fa\u790e\u77e5\u8b58\u3068\u7279\u5fb4<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-16\">\n<h3 class=\"wp-block-heading\" id=\"i-3\">1.1 \u9023\u60f3\u914d\u5217\u3068Map\u30a4\u30f3\u30bf\u30fc\u30d5\u30a7\u30fc\u30b9\u306e\u95a2\u4fc2\u6027\u3092\u7406\u89e3\u3059\u308b<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-17\">\n<p>\u9023\u60f3\u914d\u5217\uff08Associative Array\uff09\u3068\u306f\u3001\u30ad\u30fc\u3068\u5024\u306e\u30da\u30a2\u3067\u30c7\u30fc\u30bf\u3092\u7ba1\u7406\u3059\u308b\u30c7\u30fc\u30bf\u69cb\u9020\u3067\u3059\u3002Java\u3067\u306f\u3053\u306e\u30c7\u30fc\u30bfStructure\u3092<code>Map<\/code>\u30a4\u30f3\u30bf\u30fc\u30d5\u30a7\u30fc\u30b9\u3068\u3057\u3066\u5b9f\u88c5\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-21\">\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\">Map\u306e\u4e3b\u306a\u7279\u5fb4<\/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-18\">\n<li>\u30ad\u30fc\u3068\u5024\u306e\u30da\u30a2\u3067\u30c7\u30fc\u30bf\u3092\u683c\u7d0d<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-19\">\n<li>\u30ad\u30fc\u306f\u91cd\u8907\u4e0d\u53ef\u3001\u5024\u306f\u91cd\u8907\u53ef\u80fd<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-20\">\n<li>null\u3092\u30ad\u30fc\u3084\u5024\u3068\u3057\u3066\u8a31\u5bb9\uff08\u5b9f\u88c5\u30af\u30e9\u30b9\u306b\u3088\u3063\u3066\u7570\u306a\u308b\uff09<\/li>\n<\/div>\n\n\n<li>\u9806\u5e8f\u306e\u4fdd\u8a3c\u306f\u5b9f\u88c5\u30af\u30e9\u30b9\u306b\u4f9d\u5b58<\/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\u5ba3\u8a00\u306e\u57fa\u672c\u5f62\nMap&lt;String, Integer&gt; scores = new HashMap&lt;&gt;();\n\n\/\/ \u30ad\u30fc\u3068\u5024\u306e\u30da\u30a2\u3092\u8ffd\u52a0\nscores.put(\"\u7530\u4e2d\", 85);\nscores.put(\"\u9234\u6728\", 92);\n\n\/\/ \u30ad\u30fc\u3092\u4f7f\u3063\u3066\u5024\u3092\u53d6\u5f97\nint tanakaScore = scores.get(\"\u7530\u4e2d\"); \/\/ 85\u3092\u8fd4\u3059<\/pre>\n\n\n<div id=\"sgb-css-id-22\">\n<h3 class=\"wp-block-heading\" id=\"i-4\">1.2 HashMap\u3092\u4e2d\u5fc3\u3068\u3057\u305fMap\u5b9f\u88c5\u30af\u30e9\u30b9\u306e\u7a2e\u985e\u3068\u7279\u5fb4<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-23\">\n<p>Java\u306b\u306f\u7528\u9014\u306b\u5fdc\u3058\u3066\u9078\u629e\u3067\u304d\u308b\u69d8\u3005\u306aMap\u5b9f\u88c5\u30af\u30e9\u30b9\u304c\u7528\u610f\u3055\u308c\u3066\u3044\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"id-181a1234-d6ae-4042-b071-dc632a4f782f\"><div id=\"sgb-css-id-24\">\n<figure class=\"wp-block-table\"><table><thead><tr><th>\u5b9f\u88c5\u30af\u30e9\u30b9<\/th><th>\u7279\u5fb4<\/th><th>\u4e3b\u306a\u7528\u9014<\/th><\/tr><\/thead><tbody><tr><td><code>HashMap<\/code><\/td><td>\u30fb\u6700\u3082\u4e00\u822c\u7684\u306a\u5b9f\u88c5<br>\u30fbO(1)\u306e\u691c\u7d22\u6027\u80fd<br>\u30fb\u9806\u5e8f\u4fdd\u8a3c\u306a\u3057<\/td><td>\u4e00\u822c\u7684\u306a\u30ad\u30fc\u5024\u306e\u7ba1\u7406<\/td><\/tr><tr><td><code>TreeMap<\/code><\/td><td>\u30fb\u30ad\u30fc\u3067\u30bd\u30fc\u30c8<br>\u30fbO(log n)\u306e\u691c\u7d22\u6027\u80fd<br>\u30fb\u9806\u5e8f\u4fdd\u8a3c\u3042\u308a<\/td><td>\u30bd\u30fc\u30c8\u304c\u5fc5\u8981\u306a\u5834\u5408<\/td><\/tr><tr><td><code>LinkedHashMap<\/code><\/td><td>\u30fb\u633f\u5165\u9806\u5e8f\u4fdd\u6301<br>\u30fbO(1)\u306e\u691c\u7d22\u6027\u80fd<\/td><td>\u633f\u5165\u9806\u5e8f\u306e\u7dad\u6301\u304c\u5fc5\u8981\u306a\u5834\u5408<\/td><\/tr><tr><td><code>ConcurrentHashMap<\/code><\/td><td>\u30fb\u30b9\u30ec\u30c3\u30c9\u30bb\u30fc\u30d5<br>\u30fb\u4e26\u884c\u51e6\u7406\u306b\u6700\u9069\u5316<\/td><td>\u30de\u30eb\u30c1\u30b9\u30ec\u30c3\u30c9\u74b0\u5883<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div><\/div>\n\n<div id=\"sgb-css-id-25\">\n<p>\u5404\u5b9f\u88c5\u30af\u30e9\u30b9\u306e\u57fa\u672c\u7684\u306a\u4f7f\u7528\u4f8b\uff1a<\/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: \u6700\u3082\u4e00\u822c\u7684\u306a\u5b9f\u88c5\nMap&lt;String, Integer&gt; hashMap = new HashMap&lt;&gt;();\n\n\/\/ TreeMap: \u30ad\u30fc\u3067\u30bd\u30fc\u30c8\u3055\u308c\u308b\nMap&lt;String, Integer&gt; treeMap = new TreeMap&lt;&gt;();\n\n\/\/ LinkedHashMap: \u633f\u5165\u9806\u5e8f\u3092\u4fdd\u6301\nMap&lt;String, Integer&gt; linkedHashMap = new LinkedHashMap&lt;&gt;();\n\n\/\/ ConcurrentHashMap: \u30b9\u30ec\u30c3\u30c9\u30bb\u30fc\u30d5\u306a\u5b9f\u88c5\nMap&lt;String, Integer&gt; concurrentMap = new ConcurrentHashMap&lt;&gt;();<\/pre>\n\n\n<div id=\"sgb-css-id-26\">\n<h4 class=\"wp-block-heading\" id=\"i-5\">\u5b9f\u88c5\u30af\u30e9\u30b9\u306e\u9078\u629e\u6307\u91dd<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-27\">\n<p>\u30001. \u30c7\u30d5\u30a9\u30eb\u30c8\u306e\u9078\u629e\u80a2\uff1a<code>HashMap<\/code><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-28\">\n<p>\u3000\u3000\u25cf \u7279\u5225\u306a\u8981\u4ef6\u304c\u306a\u3044\u5834\u5408\u306e\u6a19\u6e96\u7684\u306a\u9078\u629e<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-29\">\n<p>\u3000\u3000\u25cf \u6700\u3082\u9ad8\u901f\u3067\u52b9\u7387\u7684\u306a\u5b9f\u88c5<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-30\">\n<p>\u30002. \u30bd\u30fc\u30c8\u304c\u5fc5\u8981\u306a\u5834\u5408\uff1a<code>TreeMap<\/code><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-31\">\n<p>\u3000\u3000\u25cf \u30ad\u30fc\u306b\u3088\u308b\u81ea\u7136\u9806\u5e8f\u3067\u30bd\u30fc\u30c8\u304c\u5fc5\u8981\u306a\u5834\u5408<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-32\">\n<p>\u3000\u3000\u25cf \u30ab\u30b9\u30bf\u30e0Comparator\u306b\u3088\u308b\u30bd\u30fc\u30c8\u3082\u53ef\u80fd<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-33\">\n<p>\u30003. \u633f\u5165\u9806\u5e8f\u306e\u4fdd\u6301\u304c\u5fc5\u8981\u306a\u5834\u5408\uff1a<code>LinkedHashMap<\/code><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-34\">\n<p>\u3000\u3000\u25cf UI\u8868\u793a\u7528\u306e\u30c7\u30fc\u30bf\u7ba1\u7406<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-35\">\n<p>\u3000\u3000\u25cf \u9806\u5e8f\u4f9d\u5b58\u306e\u51e6\u7406<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-36\">\n<p>\u30004. \u30de\u30eb\u30c1\u30b9\u30ec\u30c3\u30c9\u74b0\u5883\uff1a<code>ConcurrentHashMap<\/code><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-37\">\n<p>\u3000\u3000\u25cf \u8907\u6570\u30b9\u30ec\u30c3\u30c9\u304b\u3089\u306e\u540c\u6642\u30a2\u30af\u30bb\u30b9\u304c\u3042\u308b\u5834\u5408<\/p>\n<\/div>\n\n\n<p>\u3000\u3000\u25cf \u9ad8\u3044\u4e26\u884c\u6027\u80fd\u304c\u5fc5\u8981\u306a\u5834\u5408<\/p>\n\n\n<div id=\"sgb-css-id-38\">\n<p>\u3053\u308c\u3089\u306e\u5b9f\u88c5\u30af\u30e9\u30b9\u306f\u3001\u305d\u308c\u305e\u308c\u306e\u30e6\u30fc\u30b9\u30b1\u30fc\u30b9\u306b\u5fdc\u3058\u3066\u9069\u5207\u306b\u9078\u629e\u3059\u308b\u3053\u3068\u3067\u3001\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u306e\u8981\u4ef6\u3092\u52b9\u7387\u7684\u306b\u6e80\u305f\u3059\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-39\">\n<h2 class=\"wp-block-heading\" id=\"i-6\">\uff12\uff0e\u57fa\u672c\u7684\u306a\u4f7f\u3044\u65b9\uff1aMap\u64cd\u4f5c\u306e\u57fa\u790e\u304b\u3089\u5fdc\u7528\u307e\u3067<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-40\">\n<h3 class=\"wp-block-heading\" id=\"i-7\">2.1 \u30ad\u30fc\u3068\u5024\u306e\u8ffd\u52a0\u30fb\u53d6\u5f97\u30fb\u66f4\u65b0\u30fb\u524a\u9664\u306e\u57fa\u672c\u64cd\u4f5c<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-41\">\n<p>Map\u306e\u57fa\u672c\u7684\u306aCRUD\u64cd\u4f5c\u306b\u3064\u3044\u3066\u3001\u5b9f\u8df5\u7684\u306a\u30b3\u30fc\u30c9\u4f8b\u3068\u5171\u306b\u89e3\u8aac\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-42\">\n<h4 class=\"wp-block-heading\" id=\"i-8\">\u30c7\u30fc\u30bf\u306e\u8ffd\u52a0\u3068\u66f4\u65b0\uff08Create\/Update\uff09<\/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=\"\">Map&lt;String, User&gt; userMap = new HashMap&lt;&gt;();\n\n\/\/ put(): \u30ad\u30fc\u3068\u5024\u306e\u30da\u30a2\u3092\u8ffd\u52a0\nuserMap.put(\"user1\", new User(\"\u7530\u4e2d\u592a\u90ce\", 25));\n\n\/\/ putIfAbsent(): \u30ad\u30fc\u304c\u5b58\u5728\u3057\u306a\u3044\u5834\u5408\u306e\u307f\u8ffd\u52a0\nuserMap.putIfAbsent(\"user1\", new User(\"\u5c71\u7530\u82b1\u5b50\", 30)); \/\/ \u65e2\u5b58\u306e\u5024\u306f\u4e0a\u66f8\u304d\u3055\u308c\u306a\u3044\n\n\/\/ \u8907\u6570\u306e\u30a8\u30f3\u30c8\u30ea\u3092\u307e\u3068\u3081\u3066\u8ffd\u52a0\nMap&lt;String, User&gt; additionalUsers = Map.of(\n    \"user2\", new User(\"\u4f50\u85e4\u6b21\u90ce\", 28),\n    \"user3\", new User(\"\u9234\u6728\u4e09\u90ce\", 32)\n);\nuserMap.putAll(additionalUsers);<\/pre>\n\n\n<div id=\"sgb-css-id-43\">\n<h4 class=\"wp-block-heading\" id=\"i-9\">\u30c7\u30fc\u30bf\u306e\u53d6\u5f97\uff08Read\uff09<\/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=\"\">\/\/ get(): \u30ad\u30fc\u306b\u5bfe\u5fdc\u3059\u308b\u5024\u3092\u53d6\u5f97\nUser user = userMap.get(\"user1\");\n\n\/\/ getOrDefault(): \u30ad\u30fc\u304c\u5b58\u5728\u3057\u306a\u3044\u5834\u5408\u306b\u30c7\u30d5\u30a9\u30eb\u30c8\u5024\u3092\u8fd4\u3059\nUser defaultUser = new User(\"\u540d\u7121\u3057\", 0);\nUser unknownUser = userMap.getOrDefault(\"unknown\", defaultUser);\n\n\/\/ containsKey(): \u30ad\u30fc\u306e\u5b58\u5728\u78ba\u8a8d\nif (userMap.containsKey(\"user1\")) {\n    System.out.println(\"\u30e6\u30fc\u30b6\u30fc\u304c\u5b58\u5728\u3057\u307e\u3059\");\n}\n\n\/\/ containsValue(): \u5024\u306e\u5b58\u5728\u78ba\u8a8d\nif (userMap.containsValue(user)) {\n    System.out.println(\"\u6307\u5b9a\u3057\u305f\u30e6\u30fc\u30b6\u30fc\u304c\u5b58\u5728\u3057\u307e\u3059\");\n}<\/pre>\n\n\n<div id=\"sgb-css-id-44\">\n<h4 class=\"wp-block-heading\" id=\"i-10\">\u30c7\u30fc\u30bf\u306e\u524a\u9664\uff08Delete\uff09<\/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=\"\">\/\/ remove(): \u30ad\u30fc\u3092\u6307\u5b9a\u3057\u3066\u524a\u9664\nuserMap.remove(\"user1\");\n\n\/\/ \u6761\u4ef6\u4ed8\u304d\u524a\u9664\uff1a\u30ad\u30fc\u3068\u5024\u304c\u4e00\u81f4\u3059\u308b\u5834\u5408\u306e\u307f\u524a\u9664\nuserMap.remove(\"user2\", new User(\"\u4f50\u85e4\u6b21\u90ce\", 28));\n\n\/\/ clear(): \u5168\u3066\u306e\u30a8\u30f3\u30c8\u30ea\u3092\u524a\u9664\nuserMap.clear();<\/pre>\n\n\n<div id=\"sgb-css-id-45\">\n<h3 class=\"wp-block-heading\" id=\"i-11\">2.2 \u4fbf\u5229\u306a\u30e1\u30bd\u30c3\u30c9\u3092\u6d3b\u7528\u3057\u305f\u30de\u30c3\u30d7\u306e\u64cd\u4f5c\u30c6\u30af\u30cb\u30c3\u30af<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-46\">\n<h4 class=\"wp-block-heading\" id=\"i-12\">\u30a4\u30c6\u30ec\u30fc\u30b7\u30e7\u30f3\u51e6\u7406<\/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=\"\">Map&lt;String, Integer&gt; scores = new HashMap&lt;&gt;();\nscores.put(\"\u6570\u5b66\", 85);\nscores.put(\"\u82f1\u8a9e\", 92);\nscores.put(\"\u56fd\u8a9e\", 78);\n\n\/\/ \u30ad\u30fc\u30bb\u30c3\u30c8\u306e\u53d6\u5f97\u3068\u51e6\u7406\nfor (String subject : scores.keySet()) {\n    System.out.println(\"\u79d1\u76ee: \" + subject);\n}\n\n\/\/ \u5024\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u306e\u53d6\u5f97\u3068\u51e6\u7406\nfor (Integer score : scores.values()) {\n    System.out.println(\"\u70b9\u6570: \" + score);\n}\n\n\/\/ \u30a8\u30f3\u30c8\u30ea\u30bb\u30c3\u30c8\u3092\u4f7f\u7528\u3057\u305f\u51e6\u7406\nfor (Map.Entry&lt;String, Integer&gt; entry : scores.entrySet()) {\n    System.out.println(entry.getKey() + \": \" + entry.getValue());\n}<\/pre>\n\n\n<div id=\"sgb-css-id-47\">\n<h4 class=\"wp-block-heading\" id=\"i-13\">\u6761\u4ef6\u4ed8\u304d\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=\"\">\/\/ compute(): \u65e2\u5b58\u306e\u5024\u3092\u57fa\u306b\u65b0\u3057\u3044\u5024\u3092\u8a08\u7b97\nscores.compute(\"\u6570\u5b66\", (key, value) -&gt; value + 5); \/\/ \u6570\u5b66\u306e\u70b9\u6570\u30925\u70b9\u52a0\u7b97\n\n\/\/ computeIfPresent(): \u30ad\u30fc\u304c\u5b58\u5728\u3059\u308b\u5834\u5408\u306e\u307f\u8a08\u7b97\nscores.computeIfPresent(\"\u82f1\u8a9e\", (key, value) -&gt; value * 1.1); \/\/ \u82f1\u8a9e\u306e\u70b9\u6570\u309210%\u52a0\u7b97\n\n\/\/ computeIfAbsent(): \u30ad\u30fc\u304c\u5b58\u5728\u3057\u306a\u3044\u5834\u5408\u306e\u307f\u5024\u3092\u8a08\u7b97\u3057\u3066\u8ffd\u52a0\nscores.computeIfAbsent(\"\u7406\u79d1\", key -&gt; 80); \/\/ \u7406\u79d1\u304c\u672a\u767b\u9332\u306e\u5834\u5408\u300180\u70b9\u3092\u8a2d\u5b9a<\/pre>\n\n\n<div id=\"sgb-css-id-48\">\n<h3 class=\"wp-block-heading\" id=\"i-14\">2.3 Java 8\u4ee5\u964d\u3067\u8ffd\u52a0\u3055\u308c\u305f\u65b0\u3057\u3044Map\u64cd\u4f5c\u30e1\u30bd\u30c3\u30c9<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-49\">\n<h4 class=\"wp-block-heading\" id=\"i-15\">\u30e9\u30e0\u30c0\u5f0f\u3092\u6d3b\u7528\u3057\u305f\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=\"\">Map&lt;String, List&lt;User&gt;&gt; departmentUsers = new HashMap&lt;&gt;();\n\n\/\/ merge(): \u5024\u306e\u30de\u30fc\u30b8\u51e6\u7406\ndepartmentUsers.merge(\"\u958b\u767a\u90e8\", \n    Arrays.asList(new User(\"\u7530\u4e2d\", 25)),\n    (existingList, newList) -&gt; {\n        List&lt;User&gt; merged = new ArrayList&lt;&gt;(existingList);\n        merged.addAll(newList);\n        return merged;\n    }\n);\n\n\/\/ replaceAll(): \u5168\u3066\u306e\u5024\u3092\u5909\u63db\nscores.replaceAll((subject, score) -&gt; score + 10); \/\/ \u5168\u79d1\u76ee\u306e\u70b9\u6570\u309210\u70b9\u52a0\u7b97\n\n\/\/ forEach(): \u30a8\u30f3\u30c8\u30ea\u3054\u3068\u306e\u51e6\u7406\nscores.forEach((subject, score) -&gt; \n    System.out.printf(\"%s\u306e\u70b9\u6570: %d%n\", subject, score)\n);<\/pre>\n\n\n<div id=\"sgb-css-id-50\">\n<h4 class=\"wp-block-heading\" id=\"i-16\">Stream API\u3068\u306e\u9023\u643a<\/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=\"\">\/\/ \u30a8\u30f3\u30c8\u30ea\u306e\u30d5\u30a3\u30eb\u30bf\u30ea\u30f3\u30b0\u3068\u52a0\u5de5\nMap&lt;String, Integer&gt; highScores = scores.entrySet().stream()\n    .filter(e -&gt; e.getValue() &gt;= 80)\n    .collect(Collectors.toMap(\n        Map.Entry::getKey,\n        Map.Entry::getValue\n    ));\n\n\/\/ \u5024\u306e\u7d71\u8a08\u51e6\u7406\ndouble average = scores.values().stream()\n    .mapToInt(Integer::intValue)\n    .average()\n    .orElse(0.0);\n\n\/\/ \u30ad\u30fc\u3068\u5024\u306e\u5909\u63db\nMap&lt;String, String&gt; scoreGrades = scores.entrySet().stream()\n    .collect(Collectors.toMap(\n        Map.Entry::getKey,\n        e -&gt; e.getValue() &gt;= 90 ? \"A\" : \n             e.getValue() &gt;= 80 ? \"B\" : \n             e.getValue() &gt;= 70 ? \"C\" : \"D\"\n    ));<\/pre>\n\n\n<div id=\"sgb-css-id-51\">\n<p>\u3053\u308c\u3089\u306e\u64cd\u4f5c\u65b9\u6cd5\u3092\u7406\u89e3\u3057\u3001\u9069\u5207\u306b\u7d44\u307f\u5408\u308f\u305b\u308b\u3053\u3068\u3067\u3001\u52b9\u7387\u7684\u306a\u30c7\u30fc\u30bf\u51e6\u7406\u304c\u5b9f\u73fe\u3067\u304d\u307e\u3059\u3002\u7279\u306bJava 8\u4ee5\u964d\u3067\u8ffd\u52a0\u3055\u308c\u305f\u6a5f\u80fd\u306f\u3001\u30b3\u30fc\u30c9\u306e\u53ef\u8aad\u6027\u3068\u4fdd\u5b88\u6027\u3092\u5927\u304d\u304f\u5411\u4e0a\u3055\u305b\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-52\">\n<h2 class=\"wp-block-heading\" id=\"i-17\">\uff13\uff0e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u610f\u8b58\u3057\u305fMap\u5b9f\u88c5\u30af\u30e9\u30b9\u306e\u9078\u3073\u65b9<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-53\">\n<h3 class=\"wp-block-heading\" id=\"i-18\">3.1 HashMap\u3068TreeMap\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6bd4\u8f03<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-54\">\n<p>\u5404\u5b9f\u88c5\u30af\u30e9\u30b9\u306e\u57fa\u672c\u64cd\u4f5c\u306b\u304a\u3051\u308b\u6642\u9593\u8a08\u7b97\u91cf\u3092\u6bd4\u8f03\u3057\u3001\u9069\u5207\u306a\u9078\u629e\u57fa\u6e96\u3092\u89e3\u8aac\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-55\">\n<h4 class=\"wp-block-heading\" id=\"i-19\">\u4e3b\u306a\u64cd\u4f5c\u306e\u8a08\u7b97\u91cf\u6bd4\u8f03<\/h4>\n<\/div>\n\n<div id=\"id-b95d1744-f04b-4822-906a-8300a0e3f49a\"><div id=\"sgb-css-id-56\">\n<figure class=\"wp-block-table\"><table><thead><tr><th>\u64cd\u4f5c<\/th><th>HashMap<\/th><th>TreeMap<\/th><th>LinkedHashMap<\/th><\/tr><\/thead><tbody><tr><td>\u8ffd\u52a0\uff08<code>put<\/code>\uff09<\/td><td>O(1)<\/td><td>O(log n)<\/td><td>O(1)<\/td><\/tr><tr><td>\u53d6\u5f97\uff08<code>get<\/code>\uff09<\/td><td>O(1)<\/td><td>O(log n)<\/td><td>O(1)<\/td><\/tr><tr><td>\u524a\u9664\uff08<code>remove<\/code>\uff09<\/td><td>O(1)<\/td><td>O(log n)<\/td><td>O(1)<\/td><\/tr><tr><td>\u691c\u7d22\uff08<code>contains<\/code>\uff09<\/td><td>O(1)<\/td><td>O(log n)<\/td><td>O(1)<\/td><\/tr><tr><td>\u30a4\u30c6\u30ec\u30fc\u30b7\u30e7\u30f3<\/td><td>O(n)<\/td><td>O(n)<\/td><td>O(n)<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div><\/div>\n\n<div id=\"sgb-css-id-57\">\n<h4 class=\"wp-block-heading\" id=\"i-20\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6bd4\u8f03\u306e\u5b9f\u88c5\u4f8b<\/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 class MapPerformanceTest {\n    private static final int DATA_SIZE = 1000000;\n\n    public static void main(String[] args) {\n        \/\/ \u30c6\u30b9\u30c8\u30c7\u30fc\u30bf\u306e\u6e96\u5099\n        Map&lt;Integer, String&gt; hashMap = new HashMap&lt;&gt;();\n        Map&lt;Integer, String&gt; treeMap = new TreeMap&lt;&gt;();\n\n        \/\/ \u633f\u5165\u6027\u80fd\u306e\u6bd4\u8f03\n        long startTime = System.nanoTime();\n        for (int i = 0; i &lt; DATA_SIZE; i++) {\n            hashMap.put(i, \"Value\" + i);\n        }\n        long hashMapInsertTime = System.nanoTime() - startTime;\n\n        startTime = System.nanoTime();\n        for (int i = 0; i &lt; DATA_SIZE; i++) {\n            treeMap.put(i, \"Value\" + i);\n        }\n        long treeMapInsertTime = System.nanoTime() - startTime;\n\n        System.out.printf(\"HashMap\u633f\u5165\u6642\u9593: %d ms%n\", hashMapInsertTime \/ 1000000);\n        System.out.printf(\"TreeMap\u633f\u5165\u6642\u9593: %d ms%n\", treeMapInsertTime \/ 1000000);\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-58\">\n<h3 class=\"wp-block-heading\" id=\"i-21\">3.2 \u5927\u91cf\u30c7\u30fc\u30bf\u51e6\u7406\u6642\u306e\u6700\u9069\u306a\u5b9f\u88c5\u30af\u30e9\u30b9\u306e\u9078\u5b9a\u65b9\u6cd5<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-59\">\n<h4 class=\"wp-block-heading\" id=\"i-22\">\u30c7\u30fc\u30bf\u91cf\u3068\u30a2\u30af\u30bb\u30b9\u30d1\u30bf\u30fc\u30f3\u306b\u3088\u308b\u9078\u629e\u57fa\u6e96<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-60\">\n<p>\u30001. <strong>\u5c0f\u898f\u6a21\u30c7\u30fc\u30bf\uff08\u301c1,000\u4ef6\u7a0b\u5ea6\uff09<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-61\">\n<p>\u3000\u3000\u25cf \u3069\u306e\u5b9f\u88c5\u30af\u30e9\u30b9\u3067\u3082\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u306e\u5dee\u306f\u5c0f\u3055\u3044<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-62\">\n<p>\u3000\u3000\u25cf \u6a5f\u80fd\u8981\u4ef6\u3092\u512a\u5148\u3057\u3066\u9078\u629e\u53ef\u80fd<\/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=\"\">   \/\/ \u5c11\u91cf\u30c7\u30fc\u30bf\u306e\u5834\u5408\u306f\u6a5f\u80fd\u6027\u3092\u91cd\u8996\n   Map&lt;String, User&gt; userMap = new LinkedHashMap&lt;&gt;();  \/\/ \u9806\u5e8f\u4fdd\u6301\u304c\u5fc5\u8981\u306a\u5834\u5408<\/pre>\n\n\n<div id=\"sgb-css-id-63\">\n<p>\u30002. <strong>\u4e2d\u898f\u6a21\u30c7\u30fc\u30bf\uff081,000\u301c100,000\u4ef6\u7a0b\u5ea6\uff09<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-64\">\n<p>\u3000\u3000\u25cf \u691c\u7d22\u304c\u4e3b\u306a\u64cd\u4f5c\uff1a<code>HashMap<\/code><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-65\">\n<p>\u3000\u3000\u25cf \u30bd\u30fc\u30c8\u304c\u5fc5\u8981\uff1a<code>TreeMap<\/code><\/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=\"\">   \/\/ \u691c\u7d22\u304c\u591a\u3044\u5834\u5408\n   Map&lt;String, Product&gt; productMap = new HashMap&lt;&gt;();\n\n   \/\/ \u30bd\u30fc\u30c8\u304c\u5fc5\u8981\u306a\u5834\u5408\n   Map&lt;String, Product&gt; sortedProducts = new TreeMap&lt;&gt;();<\/pre>\n\n\n<div id=\"sgb-css-id-66\">\n<p>\u30003. <strong>\u5927\u898f\u6a21\u30c7\u30fc\u30bf\uff08100,000\u4ef6\u4ee5\u4e0a\uff09<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-67\">\n<p>\u3000\u3000\u25cf \u30e1\u30e2\u30ea\u52b9\u7387\u3092\u8003\u616e\u3057\u305f\u5b9f\u88c5\u304c\u5fc5\u8981<\/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=\"\">   \/\/ \u521d\u671f\u5bb9\u91cf\u3068\u30ed\u30fc\u30c9\u30d5\u30a1\u30af\u30bf\u30fc\u3092\u9069\u5207\u306b\u8a2d\u5b9a\n   Map&lt;String, LargeObject&gt; largeMap = new HashMap&lt;&gt;(\n       initialCapacity,  \/\/ \u4e88\u60f3\u3055\u308c\u308b\u8981\u7d20\u6570\n       0.75f            \/\/ \u30c7\u30d5\u30a9\u30eb\u30c8\u306e\u30ed\u30fc\u30c9\u30d5\u30a1\u30af\u30bf\u30fc\n   );<\/pre>\n\n\n<div id=\"sgb-css-id-68\">\n<h4 class=\"wp-block-heading\" id=\"i-23\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u30c1\u30e5\u30fc\u30cb\u30f3\u30b0\u306e\u30dd\u30a4\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 class MapPerformanceOptimization {\n    public static Map&lt;String, Object&gt; createOptimizedMap(int expectedSize) {\n        \/\/ \u521d\u671f\u5bb9\u91cf\u3092\u9069\u5207\u306b\u8a2d\u5b9a\u3057\u3066\u30ea\u30cf\u30c3\u30b7\u30e5\u3092\u6e1b\u3089\u3059\n        int capacity = (int) (expectedSize \/ 0.75f) + 1;\n\n        return new HashMap&lt;&gt;(capacity) {\n            @Override\n            public Object get(Object key) {\n                \/\/ \u30db\u30c3\u30c8\u30b9\u30dd\u30c3\u30c8\u3068\u306a\u308b\u30e1\u30bd\u30c3\u30c9\u3092\u30aa\u30fc\u30d0\u30fc\u30e9\u30a4\u30c9\n                return super.get(key);\n            }\n        };\n    }\n\n    \/\/ \u30ab\u30b9\u30bf\u30e0\u30cf\u30c3\u30b7\u30e5\u30b3\u30fc\u30c9\u306e\u5b9f\u88c5\u4f8b\n    public static class OptimizedKey {\n        private final String value;\n        private final int preCalculatedHashCode;\n\n        public OptimizedKey(String value) {\n            this.value = value;\n            \/\/ \u30cf\u30c3\u30b7\u30e5\u30b3\u30fc\u30c9\u3092\u4e8b\u524d\u8a08\u7b97\n            this.preCalculatedHashCode = value.hashCode();\n        }\n\n        @Override\n        public int hashCode() {\n            return preCalculatedHashCode;\n        }\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-69\">\n<h4 class=\"wp-block-heading\" id=\"i-24\">\u30ea\u30bd\u30fc\u30b9\u4f7f\u7528\u91cf\u306e\u6700\u9069\u5316<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-70\">\n<p>\u30001. <strong>\u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u306e\u524a\u6e1b<\/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=\"\">   \/\/ \u30ad\u30fc\u3068\u5024\u306e\u30b5\u30a4\u30ba\u3092\u6700\u5c0f\u9650\u306b\n   Map&lt;Integer, byte[]&gt; efficientMap = new HashMap&lt;&gt;();\n\n   \/\/ \u4e0d\u8981\u306a\u30a8\u30f3\u30c8\u30ea\u306e\u5b9a\u671f\u7684\u306a\u524a\u9664\n   efficientMap.entrySet().removeIf(entry -&gt; \n       entry.getValue() == null || entry.getValue().length == 0\n   );<\/pre>\n\n\n<div id=\"sgb-css-id-71\">\n<p>\u30002. <strong>\u540c\u671f\u5316\u306e\u30aa\u30fc\u30d0\u30fc\u30d8\u30c3\u30c9\u524a\u6e1b<\/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=\"\">   \/\/ \u8aad\u307f\u53d6\u308a\u304c\u591a\u3044\u5834\u5408\u306fConcurrentHashMap\u3092\u4f7f\u7528\n   Map&lt;String, Value&gt; concurrentMap = new ConcurrentHashMap&lt;&gt;();\n\n   \/\/ \u66f8\u304d\u8fbc\u307f\u30ed\u30c3\u30af\u306e\u7bc4\u56f2\u3092\u6700\u5c0f\u9650\u306b\n   concurrentMap.computeIfAbsent(key, k -&gt; {\n       \/\/ \u3053\u306e\u4e2d\u3067\u306e\u307f\u30ed\u30c3\u30af\u304c\u5fc5\u8981\n       return heavyComputation(k);\n   });<\/pre>\n\n\n<div id=\"sgb-css-id-72\">\n<p>\u3053\u308c\u3089\u306e\u9078\u629e\u57fa\u6e96\u3068\u30c1\u30e5\u30fc\u30cb\u30f3\u30b0\u30dd\u30a4\u30f3\u30c8\u3092\u7406\u89e3\u3059\u308b\u3053\u3068\u3067\u3001\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u306e\u8981\u4ef6\u306b\u6700\u9069\u306aMap\u5b9f\u88c5\u3092\u9078\u629e\u3057\u3001\u52b9\u7387\u7684\u306a\u30c7\u30fc\u30bf\u51e6\u7406\u3092\u5b9f\u73fe\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-73\">\n<h2 class=\"wp-block-heading\" id=\"i-25\">\uff14\uff0e\u5b9f\u8df5\u7684\u306aMap\u6d3b\u7528\u30d1\u30bf\u30fc\u30f3\u3068\u5b9f\u88c5\u4f8b<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-74\">\n<h3 class=\"wp-block-heading\" id=\"i-26\">4.1 \u30ad\u30e3\u30c3\u30b7\u30e5\u3068\u3057\u3066\u306eMap\u6d3b\u7528\u65b9\u6cd5<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-75\">\n<h4 class=\"wp-block-heading\" id=\"i-27\">\u30b7\u30f3\u30d7\u30eb\u306a\u30e1\u30e2\u5316\uff08\u30ad\u30e3\u30c3\u30b7\u30f3\u30b0\uff09\u306e\u5b9f\u88c5<\/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 class MemoizationExample {\n    private final Map&lt;String, BigDecimal&gt; calculationCache = new ConcurrentHashMap&lt;&gt;();\n\n    public BigDecimal calculateExpensiveValue(String input) {\n        return calculationCache.computeIfAbsent(input, key -&gt; {\n            \/\/ \u91cd\u3044\u8a08\u7b97\u51e6\u7406\n            return performExpensiveCalculation(key);\n        });\n    }\n\n    private BigDecimal performExpensiveCalculation(String input) {\n        \/\/ \u5b9f\u969b\u306e\u8a08\u7b97\u51e6\u7406\uff08\u4f8b\u3068\u3057\u3066\u5358\u7d14\u306a\u51e6\u7406\u3092\u8a18\u8f09\uff09\n        return new BigDecimal(input.length()).pow(2);\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-76\">\n<h4 class=\"wp-block-heading\" id=\"i-28\">LRU\u30ad\u30e3\u30c3\u30b7\u30e5\u306e\u5b9f\u88c5<\/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 class LRUCache&lt;K, V&gt; extends LinkedHashMap&lt;K, V&gt; {\n    private final int maxEntries;\n\n    public LRUCache(int maxEntries) {\n        super(maxEntries + 1, 0.75f, true);\n        this.maxEntries = maxEntries;\n    }\n\n    @Override\n    protected boolean removeEldestEntry(Map.Entry&lt;K, V&gt; eldest) {\n        return size() &gt; maxEntries;\n    }\n\n    \/\/ \u4f7f\u7528\u4f8b\n    public static void main(String[] args) {\n        LRUCache&lt;String, String&gt; cache = new LRUCache&lt;&gt;(3);\n        cache.put(\"key1\", \"value1\");\n        cache.put(\"key2\", \"value2\");\n        cache.put(\"key3\", \"value3\");\n        cache.put(\"key4\", \"value4\");  \/\/ key1\u304c\u81ea\u52d5\u7684\u306b\u524a\u9664\u3055\u308c\u308b\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-77\">\n<h3 class=\"wp-block-heading\" id=\"i-29\">4.2 \u30c7\u30fc\u30bf\u306e\u96c6\u8a08\u30fb\u5206\u6790\u3067\u306eMap\u6d3b\u7528\u30c6\u30af\u30cb\u30c3\u30af<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-78\">\n<h4 class=\"wp-block-heading\" id=\"i-30\">\u30b0\u30eb\u30fc\u30d7\u5316\u3068\u96c6\u8a08<\/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 class DataAggregation {\n    public static Map&lt;String, DoubleSummaryStatistics&gt; analyzeTransactions(\n            List&lt;Transaction&gt; transactions) {\n        return transactions.stream()\n            .collect(Collectors.groupingBy(\n                Transaction::getCategory,\n                Collectors.summarizingDouble(Transaction::getAmount)\n            ));\n    }\n\n    \/\/ \u8907\u6570\u6761\u4ef6\u3067\u306e\u96c6\u8a08\n    public static Map&lt;String, Map&lt;String, Long&gt;&gt; analyzeUserActivity(\n            List&lt;UserActivity&gt; activities) {\n        return activities.stream()\n            .collect(Collectors.groupingBy(\n                UserActivity::getUserId,\n                Collectors.groupingBy(\n                    UserActivity::getActivityType,\n                    Collectors.counting()\n                )\n            ));\n    }\n}\n\n\/\/ \u4f7f\u7528\u4f8b\npublic class Transaction {\n    private String category;\n    private double amount;\n    \/\/ getters, setters\n}<\/pre>\n\n\n<div id=\"sgb-css-id-79\">\n<h4 class=\"wp-block-heading\" id=\"i-31\">\u983b\u5ea6\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 class FrequencyCounter {\n    public static &lt;T&gt; Map&lt;T, Long&gt; countFrequencies(List&lt;T&gt; items) {\n        return items.stream()\n            .collect(Collectors.groupingBy(\n                item -&gt; item,\n                Collectors.counting()\n            ));\n    }\n\n    \/\/ \u30c8\u30c3\u30d7N\u4ef6\u306e\u53d6\u5f97\n    public static &lt;T&gt; List&lt;Map.Entry&lt;T, Long&gt;&gt; getTopN(\n            Map&lt;T, Long&gt; frequencies, int n) {\n        return frequencies.entrySet().stream()\n            .sorted(Map.Entry.&lt;T, Long&gt;comparingByValue().reversed())\n            .limit(n)\n            .collect(Collectors.toList());\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-80\">\n<h3 class=\"wp-block-heading\" id=\"i-32\">4.3 \u8907\u6570\u306eMap\u3092\u7d44\u307f\u5408\u308f\u305b\u305f\u9ad8\u5ea6\u306a\u5b9f\u88c5\u30d1\u30bf\u30fc\u30f3<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-81\">\n<h4 class=\"wp-block-heading\" id=\"i-33\">\u53cc\u65b9\u5411\u30de\u30c3\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 class BiDirectionalMap&lt;K, V&gt; {\n    private final Map&lt;K, V&gt; forward = new HashMap&lt;&gt;();\n    private final Map&lt;V, K&gt; backward = new HashMap&lt;&gt;();\n\n    public void put(K key, V value) {\n        forward.put(key, value);\n        backward.put(value, key);\n    }\n\n    public V getByKey(K key) {\n        return forward.get(key);\n    }\n\n    public K getByValue(V value) {\n        return backward.get(value);\n    }\n\n    public void remove(K key) {\n        V value = forward.remove(key);\n        if (value != null) {\n            backward.remove(value);\n        }\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-82\">\n<h4 class=\"wp-block-heading\" id=\"i-34\">\u968e\u5c64\u7684\u30c7\u30fc\u30bf\u69cb\u9020\u306e\u5b9f\u88c5<\/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 class HierarchicalMap {\n    private static class Node {\n        Map&lt;String, Node&gt; children = new HashMap&lt;&gt;();\n        String value;\n    }\n\n    private final Node root = new Node();\n\n    public void put(String[] path, String value) {\n        Node current = root;\n        for (String component : path) {\n            current = current.children.computeIfAbsent(\n                component, k -&gt; new Node()\n            );\n        }\n        current.value = value;\n    }\n\n    public String get(String[] path) {\n        Node current = root;\n        for (String component : path) {\n            current = current.children.get(component);\n            if (current == null) {\n                return null;\n            }\n        }\n        return current.value;\n    }\n\n    \/\/ \u4f7f\u7528\u4f8b\n    public static void main(String[] args) {\n        HierarchicalMap hMap = new HierarchicalMap();\n        hMap.put(new String[]{\"config\", \"database\", \"url\"}, \"jdbc:mysql:\/\/localhost:3306\/db\");\n        hMap.put(new String[]{\"config\", \"database\", \"username\"}, \"root\");\n\n        String dbUrl = hMap.get(new String[]{\"config\", \"database\", \"url\"});\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-83\">\n<p>\u3053\u308c\u3089\u306e\u5b9f\u88c5\u30d1\u30bf\u30fc\u30f3\u306f\u3001\u5b9f\u969b\u306e\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u958b\u767a\u3067\u983b\u7e41\u306b\u5fc5\u8981\u3068\u306a\u308b\u6a5f\u80fd\u3092\u63d0\u4f9b\u3057\u307e\u3059\u3002\u72b6\u6cc1\u306b\u5fdc\u3058\u3066\u9069\u5207\u306a\u30d1\u30bf\u30fc\u30f3\u3092\u9078\u629e\u3057\u3001\u5fc5\u8981\u306b\u5fdc\u3058\u3066\u30ab\u30b9\u30bf\u30de\u30a4\u30ba\u3059\u308b\u3053\u3068\u3067\u3001\u52b9\u7387\u7684\u306a\u30c7\u30fc\u30bf\u7ba1\u7406\u3092\u5b9f\u73fe\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-84\">\n<h2 class=\"wp-block-heading\" id=\"i-35\">\uff15\uff0eMap\u3092\u4f7f\u7528\u3059\u308b\u969b\u306e\u6ce8\u610f\u70b9\u3068\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-85\">\n<h3 class=\"wp-block-heading\" id=\"i-36\">5.1 Null\u30dd\u30a4\u30f3\u30bf\u3084ConcurrentModificationException\u306e\u56de\u907f\u65b9\u6cd5<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-86\">\n<h4 class=\"wp-block-heading\" id=\"i-37\">Null\u30dd\u30a4\u30f3\u30bf\u5bfe\u7b56<\/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 class NullSafeMapOperations {\n    \/\/ Null\u30bb\u30fc\u30d5\u306a\u30b2\u30c3\u30bf\u30fc\u5b9f\u88c5\n    public static &lt;K, V&gt; V getValueSafely(Map&lt;K, V&gt; map, K key) {\n        if (map == null) {\n            return null;\n        }\n        return map.get(key);\n    }\n\n    \/\/ Optional \u3092\u4f7f\u7528\u3057\u305f\u3088\u308a\u5b89\u5168\u306a\u5b9f\u88c5\n    public static &lt;K, V&gt; Optional&lt;V&gt; getValueAsOptional(Map&lt;K, V&gt; map, K key) {\n        return Optional.ofNullable(map)\n            .map(m -&gt; m.get(key));\n    }\n\n    \/\/ Null\u30c1\u30a7\u30c3\u30af\u3092\u542b\u3080put\u64cd\u4f5c\n    public static &lt;K, V&gt; void putSafely(Map&lt;K, V&gt; map, K key, V value) {\n        if (map != null &amp;&amp; key != null) {\n            map.put(key, value);\n        }\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-87\">\n<h4 class=\"wp-block-heading\" id=\"i-38\">ConcurrentModificationException\u5bfe\u7b56<\/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 class SafeMapIteration {\n    \/\/ \u5b89\u5168\u306a\u30a4\u30c6\u30ec\u30fc\u30b7\u30e7\u30f3\u5b9f\u88c5\n    public static &lt;K, V&gt; void safeIteration(Map&lt;K, V&gt; map) {\n        \/\/ \u65b0\u3057\u3044ArrayList\u3092\u4f5c\u6210\u3057\u3066\u30a4\u30c6\u30ec\u30fc\u30b7\u30e7\u30f3\n        new ArrayList&lt;&gt;(map.entrySet()).forEach(entry -&gt; {\n            \/\/ \u30a8\u30f3\u30c8\u30ea\u306e\u51e6\u7406\n            processEntry(entry);\n        });\n    }\n\n    \/\/ removeIf \u3092\u4f7f\u7528\u3057\u305f\u5b89\u5168\u306a\u524a\u9664\n    public static &lt;K, V&gt; void safeRemoval(Map&lt;K, V&gt; map, Predicate&lt;Map.Entry&lt;K, V&gt;&gt; condition) {\n        map.entrySet().removeIf(condition);\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-88\">\n<h3 class=\"wp-block-heading\" id=\"i-39\">5.2 \u30b9\u30ec\u30c3\u30c9\u30bb\u30fc\u30d5\u306a\u5b9f\u88c5\u306e\u305f\u3081\u306e\u30dd\u30a4\u30f3\u30c8<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-89\">\n<h4 class=\"wp-block-heading\" id=\"i-40\">\u540c\u671f\u5316\u306e\u9069\u5207\u306a\u5b9f\u88c5<\/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 class ThreadSafeMap&lt;K, V&gt; {\n    private final Map&lt;K, V&gt; map = new ConcurrentHashMap&lt;&gt;();\n\n    \/\/ \u30a2\u30c8\u30df\u30c3\u30af\u306a\u66f4\u65b0\u64cd\u4f5c\n    public V updateValue(K key, UnaryOperator&lt;V&gt; updateFunction) {\n        return map.compute(key, (k, v) -&gt; updateFunction.apply(v));\n    }\n\n    \/\/ \u8907\u6570\u306e\u64cd\u4f5c\u3092\u30a2\u30c8\u30df\u30c3\u30af\u306b\u5b9f\u884c\n    public void atomicUpdate(K key, V newValue) {\n        map.compute(key, (k, oldValue) -&gt; {\n            \/\/ \u8907\u96d1\u306a\u66f4\u65b0\u30ed\u30b8\u30c3\u30af\n            if (oldValue == null) {\n                return newValue;\n            }\n            \/\/ \u6761\u4ef6\u306b\u57fa\u3065\u304f\u66f4\u65b0\n            return updateValueBasedOnCondition(oldValue, newValue);\n        });\n    }\n\n    private V updateValueBasedOnCondition(V oldValue, V newValue) {\n        \/\/ \u66f4\u65b0\u30ed\u30b8\u30c3\u30af\u306e\u5b9f\u88c5\n        return newValue;\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-90\">\n<h4 class=\"wp-block-heading\" id=\"i-41\">\u8aad\u307f\u53d6\u308a\/\u66f8\u304d\u8fbc\u307f\u306e\u6700\u9069\u5316<\/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 class ReadWriteOptimizedMap&lt;K, V&gt; {\n    private final Map&lt;K, V&gt; map = new ConcurrentHashMap&lt;&gt;();\n    private final ReadWriteLock lock = new ReentrantReadWriteLock();\n\n    \/\/ \u8aad\u307f\u53d6\u308a\u64cd\u4f5c\uff08\u8907\u6570\u30b9\u30ec\u30c3\u30c9\u3067\u540c\u6642\u5b9f\u884c\u53ef\u80fd\uff09\n    public V get(K key) {\n        lock.readLock().lock();\n        try {\n            return map.get(key);\n        } finally {\n            lock.readLock().unlock();\n        }\n    }\n\n    \/\/ \u66f8\u304d\u8fbc\u307f\u64cd\u4f5c\uff08\u6392\u4ed6\u5236\u5fa1\uff09\n    public void put(K key, V value) {\n        lock.writeLock().lock();\n        try {\n            map.put(key, value);\n        } finally {\n            lock.writeLock().unlock();\n        }\n    }\n\n    \/\/ \u30d0\u30c3\u30c1\u66f4\u65b0\n    public void batchUpdate(Map&lt;K, V&gt; updates) {\n        lock.writeLock().lock();\n        try {\n            map.putAll(updates);\n        } finally {\n            lock.writeLock().unlock();\n        }\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-91\">\n<h3 class=\"wp-block-heading\" id=\"i-42\">5.3 \u30e1\u30e2\u30ea\u52b9\u7387\u3092\u8003\u616e\u3057\u305fMap\u5b9f\u88c5\u306e\u30b3\u30c4<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-92\">\n<h4 class=\"wp-block-heading\" id=\"i-43\">\u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u306e\u6700\u9069\u5316<\/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 class MemoryEfficientMap&lt;K, V&gt; {\n    \/\/ \u521d\u671f\u5bb9\u91cf\u3068\u30ed\u30fc\u30c9\u30d5\u30a1\u30af\u30bf\u30fc\u306e\u6700\u9069\u5316\n    private final Map&lt;K, V&gt; map;\n\n    public MemoryEfficientMap(int expectedSize) {\n        \/\/ \u4e88\u60f3\u30b5\u30a4\u30ba\u306b\u57fa\u3065\u3044\u3066\u521d\u671f\u5bb9\u91cf\u3092\u8a2d\u5b9a\n        int capacity = (int) Math.ceil(expectedSize \/ 0.75);\n        this.map = new HashMap&lt;&gt;(capacity, 0.75f);\n    }\n\n    \/\/ \u5f31\u53c2\u7167\u3092\u4f7f\u7528\u3057\u305f\u30ad\u30e3\u30c3\u30b7\u30e5\u5b9f\u88c5\n    private final Map&lt;K, WeakReference&lt;V&gt;&gt; weakMap = \n        new WeakHashMap&lt;&gt;();\n\n    public void putWeak(K key, V value) {\n        weakMap.put(key, new WeakReference&lt;&gt;(value));\n    }\n\n    public V getWeak(K key) {\n        WeakReference&lt;V&gt; ref = weakMap.get(key);\n        return ref != null ? ref.get() : null;\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-93\">\n<h4 class=\"wp-block-heading\" id=\"i-44\">\u30e1\u30e2\u30ea\u30ea\u30fc\u30af\u9632\u6b62\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-94\">\n<p>\u30001. <strong>\u9069\u5207\u306a\u30af\u30ea\u30fc\u30f3\u30a2\u30c3\u30d7<\/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 MapCleanupExample {\n    private final Map&lt;String, Object&gt; resourceMap = new HashMap&lt;&gt;();\n\n    \/\/ \u5b9a\u671f\u7684\u306a\u30af\u30ea\u30fc\u30f3\u30a2\u30c3\u30d7\n    public void cleanup() {\n        resourceMap.entrySet().removeIf(entry -&gt; \n            isResourceExpired(entry.getValue())\n        );\n    }\n\n    \/\/ \u4f7f\u7528\u7d42\u4e86\u5f8c\u306e\u660e\u793a\u7684\u306a\u30af\u30ea\u30fc\u30f3\u30a2\u30c3\u30d7\n    public void releaseResources() {\n        resourceMap.values().forEach(this::closeResource);\n        resourceMap.clear();\n    }\n\n    private boolean isResourceExpired(Object resource) {\n        \/\/ \u30ea\u30bd\u30fc\u30b9\u306e\u6709\u52b9\u671f\u9650\u30c1\u30a7\u30c3\u30af\u30ed\u30b8\u30c3\u30af\n        return false;\n    }\n\n    private void closeResource(Object resource) {\n        \/\/ \u30ea\u30bd\u30fc\u30b9\u306e\u30af\u30ed\u30fc\u30ba\u51e6\u7406\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-95\">\n<p>\u3053\u308c\u3089\u306e\u5b9f\u88c5\u30d1\u30bf\u30fc\u30f3\u3068\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\u3092\u9069\u5207\u306b\u9069\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u5b89\u5168\u3067\u52b9\u7387\u7684\u306aMap\u306e\u5229\u7528\u304c\u53ef\u80fd\u306b\u306a\u308a\u307e\u3059\u3002\u7279\u306b\u5927\u898f\u6a21\u306a\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3084\u30de\u30eb\u30c1\u30b9\u30ec\u30c3\u30c9\u74b0\u5883\u3067\u306f\u3001\u3053\u308c\u3089\u306e\u6ce8\u610f\u70b9\u3092\u610f\u8b58\u3059\u308b\u3053\u3068\u304c\u91cd\u8981\u3067\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-96\">\n<h2 class=\"wp-block-heading\" id=\"i-45\">\uff16\uff0e\u3088\u304f\u3042\u308b\u30d0\u30b0\u3068\u5bfe\u51e6\u6cd5\uff1a\u30c8\u30e9\u30d6\u30eb\u30b7\u30e5\u30fc\u30c6\u30a3\u30f3\u30b0\u30ac\u30a4\u30c9<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-97\">\n<h3 class=\"wp-block-heading\" id=\"i-46\">6.1 \u30ad\u30fc\u306e\u91cd\u8907\u3084\u60f3\u5b9a\u5916\u306e\u4e0a\u66f8\u304d\u3078\u306e\u5bfe\u51e6<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-98\">\n<h4 class=\"wp-block-heading\" id=\"i-47\">\u554f\u984c1\uff1a \u30ab\u30b9\u30bf\u30e0\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u30ad\u30fc\u3068\u3057\u3066\u4f7f\u7528\u6642\u306e\u91cd\u8907<\/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 class MapKeyIssues {\n    \/\/ \u554f\u984c\u306e\u3042\u308b\u30ad\u30fc\u30af\u30e9\u30b9\u306e\u4f8b\n    public static class ProblematicKey {\n        private final String id;\n        private final String type;\n\n        public ProblematicKey(String id, String type) {\n            this.id = id;\n            this.type = type;\n        }\n\n        \/\/ hashCode\u306e\u5b9f\u88c5\u304c\u306a\u3044\uff01\n        \/\/ equals\u306e\u5b9f\u88c5\u304c\u306a\u3044\uff01\n    }\n\n    \/\/ \u4fee\u6b63\u3055\u308c\u305f\u30ad\u30fc\u30af\u30e9\u30b9\n    public static class CorrectKey {\n        private final String id;\n        private final String type;\n\n        public CorrectKey(String id, String type) {\n            this.id = id;\n            this.type = type;\n        }\n\n        @Override\n        public boolean equals(Object o) {\n            if (this == o) return true;\n            if (o == null || getClass() != o.getClass()) return false;\n            CorrectKey that = (CorrectKey) o;\n            return Objects.equals(id, that.id) &amp;&amp; \n                   Objects.equals(type, that.type);\n        }\n\n        @Override\n        public int hashCode() {\n            return Objects.hash(id, type);\n        }\n    }\n\n    \/\/ \u4f7f\u7528\u4f8b\u3068\u554f\u984c\u306e\u691c\u8a3c\n    public static void demonstrateProblem() {\n        Map&lt;ProblematicKey, String&gt; problematicMap = new HashMap&lt;&gt;();\n        ProblematicKey key1 = new ProblematicKey(\"1\", \"A\");\n        ProblematicKey key2 = new ProblematicKey(\"1\", \"A\");\n\n        problematicMap.put(key1, \"value1\");\n        problematicMap.put(key2, \"value2\");\n\n        \/\/ \u540c\u3058\u5185\u5bb9\u306e\u30ad\u30fc\u306a\u306e\u306b2\u3064\u306e\u7570\u306a\u308b\u30a8\u30f3\u30c8\u30ea\u3068\u3057\u3066\u6271\u308f\u308c\u308b\n        System.out.println(\"Size: \" + problematicMap.size()); \/\/ 2\u304c\u51fa\u529b\u3055\u308c\u308b\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-99\">\n<h4 class=\"wp-block-heading\" id=\"i-48\">\u554f\u984c2\uff1a \u610f\u56f3\u3057\u306a\u3044\u4e0a\u66f8\u304d\u306e\u9632\u6b62<\/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 class MapOverwritePrevention {\n    \/\/ \u4e0a\u66f8\u304d\u9632\u6b62\u7528\u306e\u30e6\u30fc\u30c6\u30a3\u30ea\u30c6\u30a3\u30e1\u30bd\u30c3\u30c9\n    public static &lt;K, V&gt; boolean putIfNotExists(\n            Map&lt;K, V&gt; map, K key, V value) {\n        if (map.containsKey(key)) {\n            return false;\n        }\n        map.put(key, value);\n        return true;\n    }\n\n    \/\/ \u5024\u306e\u5909\u66f4\u3092\u8ffd\u8de1\u3059\u308bMap\u5b9f\u88c5\n    public static class AuditingMap&lt;K, V&gt; extends HashMap&lt;K, V&gt; {\n        private final List&lt;String&gt; changeLog = new ArrayList&lt;&gt;();\n\n        @Override\n        public V put(K key, V value) {\n            V oldValue = get(key);\n            if (oldValue != null) {\n                changeLog.add(String.format(\n                    \"Key '%s' value overwritten: %s -&gt; %s\",\n                    key, oldValue, value\n                ));\n            }\n            return super.put(key, value);\n        }\n\n        public List&lt;String&gt; getChangeLog() {\n            return new ArrayList&lt;&gt;(changeLog);\n        }\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-100\">\n<h3 class=\"wp-block-heading\" id=\"i-49\">6.2 \u30e1\u30e2\u30ea\u30ea\u30fc\u30af\u3092\u9632\u3050\u305f\u3081\u306e\u5b9f\u88c5\u65b9\u6cd5<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-101\">\n<h4 class=\"wp-block-heading\" id=\"i-50\">\u4e00\u822c\u7684\u306a\u30e1\u30e2\u30ea\u30ea\u30fc\u30af\u30d1\u30bf\u30fc\u30f3\u3068\u305d\u306e\u5bfe\u7b56<\/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 class MemoryLeakPrevention {\n    \/\/ \u30e1\u30e2\u30ea\u30ea\u30fc\u30af\u304c\u767a\u751f\u3057\u3084\u3059\u3044\u5b9f\u88c5\u4f8b\n    private static class LeakingCache {\n        private final Map&lt;String, Object&gt; cache = new HashMap&lt;&gt;();\n\n        public void addToCache(String key, Object value) {\n            cache.put(key, value);  \/\/ \u30c7\u30fc\u30bf\u304c\u969b\u9650\u306a\u304f\u84c4\u7a4d\u3055\u308c\u308b\n        }\n    }\n\n    \/\/ \u6539\u5584\u3055\u308c\u305f\u5b9f\u88c5\n    private static class BoundedCache {\n        private final int maxSize;\n        private final Map&lt;String, Object&gt; cache;\n\n        public BoundedCache(int maxSize) {\n            this.maxSize = maxSize;\n            this.cache = new LinkedHashMap&lt;String, Object&gt;(\n                maxSize, 0.75f, true) {\n                @Override\n                protected boolean removeEldestEntry(\n                        Map.Entry&lt;String, Object&gt; eldest) {\n                    return size() &gt; maxSize;\n                }\n            };\n        }\n\n        public void addToCache(String key, Object value) {\n            cache.put(key, value);\n        }\n    }\n\n    \/\/ \u9577\u671f\u7a3c\u50cd\u30b7\u30b9\u30c6\u30e0\u3067\u306e\u30e1\u30e2\u30ea\u30ea\u30fc\u30af\u5bfe\u7b56\n    public static class ResourceManager {\n        private final Map&lt;String, WeakReference&lt;Resource&gt;&gt; resources = \n            new WeakHashMap&lt;&gt;();\n        private final ScheduledExecutorService cleanup = \n            Executors.newSingleThreadScheduledExecutor();\n\n        public ResourceManager() {\n            \/\/ \u5b9a\u671f\u7684\u306a\u30af\u30ea\u30fc\u30f3\u30a2\u30c3\u30d7\u51e6\u7406\u3092\u30b9\u30b1\u30b8\u30e5\u30fc\u30eb\n            cleanup.scheduleAtFixedRate(\n                this::cleanupResources,\n                1, 1, TimeUnit.HOURS\n            );\n        }\n\n        private void cleanupResources() {\n            resources.entrySet().removeIf(entry -&gt; \n                entry.getValue().get() == null ||\n                !isResourceValid(entry.getValue().get())\n            );\n        }\n\n        private boolean isResourceValid(Resource resource) {\n            \/\/ \u30ea\u30bd\u30fc\u30b9\u306e\u6709\u52b9\u6027\u30c1\u30a7\u30c3\u30af\n            return resource != null &amp;&amp; resource.isValid();\n        }\n\n        \/\/ \u30ea\u30bd\u30fc\u30b9\u30af\u30e9\u30b9\n        private static class Resource {\n            private boolean valid = true;\n            public boolean isValid() {\n                return valid;\n            }\n        }\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-102\">\n<h4 class=\"wp-block-heading\" id=\"i-51\">\u30c7\u30d0\u30c3\u30b0\u3068\u30e2\u30cb\u30bf\u30ea\u30f3\u30b0\u306e\u305f\u3081\u306e\u30c4\u30fc\u30eb\u6d3b\u7528<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-103\">\n<p>\u30001. <strong>\u30e1\u30e2\u30ea\u30ea\u30fc\u30af\u691c\u51fa<\/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 MapMonitoring {\n    private final Map&lt;String, Object&gt; monitoredMap = new HashMap&lt;&gt;();\n    private final AtomicInteger putCount = new AtomicInteger();\n    private final AtomicInteger removeCount = new AtomicInteger();\n\n    \/\/ \u64cd\u4f5c\u3092\u30e2\u30cb\u30bf\u30ea\u30f3\u30b0\n    public void put(String key, Object value) {\n        monitoredMap.put(key, value);\n        putCount.incrementAndGet();\n        logMapStats();\n    }\n\n    public Object remove(String key) {\n        Object removed = monitoredMap.remove(key);\n        if (removed != null) {\n            removeCount.incrementAndGet();\n        }\n        logMapStats();\n        return removed;\n    }\n\n    private void logMapStats() {\n        System.out.printf(\n            \"Map size: %d, Total puts: %d, Total removes: %d%n\",\n            monitoredMap.size(),\n            putCount.get(),\n            removeCount.get()\n        );\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-104\">\n<p>\u3053\u308c\u3089\u306e\u5bfe\u7b56\u3092\u5b9f\u88c5\u3059\u308b\u3053\u3068\u3067\u3001\u591a\u304f\u306e\u4e00\u822c\u7684\u306aMap\u95a2\u9023\u306e\u554f\u984c\u3092\u4e88\u9632\u3057\u3001\u767a\u751f\u3057\u305f\u5834\u5408\u3082\u8fc5\u901f\u306b\u5bfe\u51e6\u3067\u304d\u308b\u3088\u3046\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-105\">\n<h2 class=\"wp-block-heading\" id=\"i-52\">\uff17\uff0e\u767a\u5c55\u7684\u306a\u30c8\u30d4\u30c3\u30af\uff1aMap\u306e\u9ad8\u5ea6\u306a\u4f7f\u3044\u65b9<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-106\">\n<h3 class=\"wp-block-heading\" id=\"i-53\">7.1 \u30ab\u30b9\u30bf\u30e0\u30ad\u30fc\u30af\u30e9\u30b9\u306e\u5b9f\u88c5\u65b9\u6cd5\u3068\u30dd\u30a4\u30f3\u30c8<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-107\">\n<h4 class=\"wp-block-heading\" id=\"i-54\">\u30a4\u30df\u30e5\u30fc\u30bf\u30d6\u30eb\u306a\u30ad\u30fc\u30af\u30e9\u30b9\u306e\u5b9f\u88c5<\/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 final class ImmutableKey {\n    private final String id;\n    private final LocalDateTime timestamp;\n    private final int hashCode;  \/\/ \u4e8b\u524d\u8a08\u7b97\u3055\u308c\u305f\u30cf\u30c3\u30b7\u30e5\u30b3\u30fc\u30c9\n\n    public ImmutableKey(String id, LocalDateTime timestamp) {\n        this.id = id;\n        this.timestamp = timestamp;\n        this.hashCode = Objects.hash(id, timestamp);\n    }\n\n    \/\/ \u5168\u30d5\u30a3\u30fc\u30eb\u30c9\u3092final\u3068\u3057\u3001setter\u4e0d\u8981\n    public String getId() {\n        return id;\n    }\n\n    public LocalDateTime getTimestamp() {\n        return timestamp;\n    }\n\n    @Override\n    public boolean equals(Object o) {\n        if (this == o) return true;\n        if (!(o instanceof ImmutableKey)) return false;\n        ImmutableKey that = (ImmutableKey) o;\n        return Objects.equals(id, that.id) &amp;&amp; \n               Objects.equals(timestamp, that.timestamp);\n    }\n\n    @Override\n    public int hashCode() {\n        return hashCode;  \/\/ \u4e8b\u524d\u8a08\u7b97\u3055\u308c\u305f\u5024\u3092\u8fd4\u3059\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-108\">\n<h4 class=\"wp-block-heading\" id=\"i-55\">\u8907\u5408\u30ad\u30fc\u306e\u52b9\u7387\u7684\u306a\u5b9f\u88c5<\/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 class CompositeKey&lt;T1 extends Comparable&lt;T1&gt;, T2 extends Comparable&lt;T2&gt;&gt; \n        implements Comparable&lt;CompositeKey&lt;T1, T2&gt;&gt; {\n\n    private final T1 first;\n    private final T2 second;\n\n    public CompositeKey(T1 first, T2 second) {\n        this.first = first;\n        this.second = second;\n    }\n\n    @Override\n    public int compareTo(CompositeKey&lt;T1, T2&gt; other) {\n        int firstComparison = first.compareTo(other.first);\n        if (firstComparison != 0) {\n            return firstComparison;\n        }\n        return second.compareTo(other.second);\n    }\n\n    \/\/ equals, hashCode\u5b9f\u88c5\u306f\u7701\u7565\n\n    \/\/ \u4f7f\u7528\u4f8b\n    public static void main(String[] args) {\n        Map&lt;CompositeKey&lt;String, Integer&gt;, String&gt; map = new TreeMap&lt;&gt;();\n        map.put(new CompositeKey&lt;&gt;(\"A\", 1), \"Value1\");\n        map.put(new CompositeKey&lt;&gt;(\"A\", 2), \"Value2\");\n        map.put(new CompositeKey&lt;&gt;(\"B\", 1), \"Value3\");\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-109\">\n<h3 class=\"wp-block-heading\" id=\"i-56\">7.2 Java 9\u4ee5\u964d\u306e\u65b0\u6a5f\u80fd\u3068Map\u306e\u9032\u5316<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-110\">\n<h4 class=\"wp-block-heading\" id=\"i-57\">\u65b0\u3057\u3044\u30d5\u30a1\u30af\u30c8\u30ea\u30e1\u30bd\u30c3\u30c9<\/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 class ModernMapFeatures {\n    \/\/ Java 9\u306eMap.of\u30e1\u30bd\u30c3\u30c9\n    public static void demonstrateImmutableMaps() {\n        \/\/ \u4e0d\u5909Map\u306e\u4f5c\u6210\n        Map&lt;String, Integer&gt; map1 = Map.of(\n            \"one\", 1,\n            \"two\", 2,\n            \"three\", 3\n        );\n\n        \/\/ \u30a8\u30f3\u30c8\u30ea\u306e\u96c6\u5408\u304b\u3089Map\u3092\u4f5c\u6210\n        Map&lt;String, Integer&gt; map2 = Map.ofEntries(\n            Map.entry(\"four\", 4),\n            Map.entry(\"five\", 5)\n        );\n    }\n\n    \/\/ Java 10\u306ecopyOf\u30e1\u30bd\u30c3\u30c9\n    public static &lt;K, V&gt; Map&lt;K, V&gt; createImmutableCopy(Map&lt;K, V&gt; original) {\n        return Map.copyOf(original);\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-111\">\n<h4 class=\"wp-block-heading\" id=\"i-58\">\u65b0\u3057\u3044\u30e1\u30bd\u30c3\u30c9\u306e\u6d3b\u7528\u4f8b<\/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 class EnhancedMapOperations {\n    public static void demonstrateModernOperations() {\n        Map&lt;String, Integer&gt; scores = new HashMap&lt;&gt;();\n        scores.put(\"Alice\", 95);\n        scores.put(\"Bob\", 85);\n\n        \/\/ putIfAbsent\u306e\u4ee3\u308f\u308a\u306bcomputeIfAbsent\u3092\u4f7f\u7528\n        scores.computeIfAbsent(\"Charlie\", key -&gt; calculateInitialScore(key));\n\n        \/\/ \u30de\u30fc\u30b8\u64cd\u4f5c\n        scores.merge(\"Alice\", 5, (oldValue, value) -&gt; oldValue + value);\n\n        \/\/ \u6761\u4ef6\u4ed8\u304d\u524a\u9664\n        scores.remove(\"Bob\", 85);  \/\/ \u5024\u304c85\u306e\u5834\u5408\u306e\u307f\u524a\u9664\n\n        \/\/ \u30c7\u30d5\u30a9\u30eb\u30c8\u5024\u3092\u4f7f\u7528\u3057\u305f\u53d6\u5f97\n        int davidScore = scores.getOrDefault(\"David\", 0);\n    }\n\n    private static Integer calculateInitialScore(String name) {\n        \/\/ \u521d\u671f\u30b9\u30b3\u30a2\u306e\u8a08\u7b97\u30ed\u30b8\u30c3\u30af\n        return 70;\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-112\">\n<h4 class=\"wp-block-heading\" id=\"i-59\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316\u30c6\u30af\u30cb\u30c3\u30af<\/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 class OptimizedMapOperations {\n    \/\/ \u9ad8\u6027\u80fd\u306a\u8907\u6570\u30ad\u30fc\u691c\u7d22\n    public static &lt;K, V&gt; Map&lt;K, V&gt; findAllMatching(\n            Map&lt;K, V&gt; source, Collection&lt;K&gt; keys) {\n        return keys.stream()\n            .filter(source::containsKey)\n            .collect(Collectors.toMap(\n                key -&gt; key,\n                source::get,\n                (v1, v2) -&gt; v1,\n                () -&gt; new HashMap&lt;&gt;(Math.min(keys.size(), source.size()))\n            ));\n    }\n\n    \/\/ \u30d0\u30eb\u30af\u64cd\u4f5c\u306e\u6700\u9069\u5316\n    public static &lt;K, V&gt; void bulkUpdate(\n            Map&lt;K, V&gt; map, \n            List&lt;Map.Entry&lt;K, V&gt;&gt; updates) {\n        \/\/ \u30b5\u30a4\u30ba\u30d9\u30fc\u30b9\u306e\u6700\u9069\u5316\n        if (updates.size() &gt; map.size() \/ 2) {\n            \/\/ \u5927\u91cf\u66f4\u65b0\u306e\u5834\u5408\u306f\u65b0\u3057\u3044\u30de\u30c3\u30d7\u3092\u4f5c\u6210\n            Map&lt;K, V&gt; newMap = new HashMap&lt;&gt;(map);\n            updates.forEach(entry -&gt; \n                newMap.put(entry.getKey(), entry.getValue())\n            );\n            map.clear();\n            map.putAll(newMap);\n        } else {\n            \/\/ \u5c11\u91cf\u66f4\u65b0\u306e\u5834\u5408\u306f\u76f4\u63a5\u66f4\u65b0\n            updates.forEach(entry -&gt; \n                map.put(entry.getKey(), entry.getValue())\n            );\n        }\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-113\">\n<p>\u3053\u308c\u3089\u306e\u9ad8\u5ea6\u306a\u6a5f\u80fd\u3068\u6700\u9069\u5316\u30c6\u30af\u30cb\u30c3\u30af\u3092\u6d3b\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u3088\u308a\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u306e\u9ad8\u3044\u3001\u30e1\u30f3\u30c6\u30ca\u30f3\u30b9\u6027\u306e\u826f\u3044\u30b3\u30fc\u30c9\u3092\u66f8\u304f\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-114\">\n<h2 class=\"wp-block-heading\" id=\"i-60\">\u307e\u3068\u3081\uff1a\u52b9\u679c\u7684\u306aMap\u6d3b\u7528\u306e\u305f\u3081\u306b\u62bc\u3055\u3048\u308b\u3079\u304d\u30dd\u30a4\u30f3\u30c8<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-115\">\n<p>\u672c\u8a18\u4e8b\u3067\u306f\u3001Java\u306e\u9023\u60f3\u914d\u5217\uff08Map\uff09\u306b\u3064\u3044\u3066\u3001\u57fa\u790e\u304b\u3089\u5fdc\u7528\u307e\u3067\u5e45\u5e83\u304f\u89e3\u8aac\u3057\u3066\u304d\u307e\u3057\u305f\u3002\u3053\u3053\u3067\u3001\u5b9f\u8df5\u3067\u6d3b\u7528\u3059\u308b\u305f\u3081\u306e\u91cd\u8981\u306a\u30dd\u30a4\u30f3\u30c8\u3092\u6574\u7406\u3057\u307e\u3057\u3087\u3046\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-116\">\n<h4 class=\"wp-block-heading\" id=\"i-61\">1. \u5b9f\u8df5\u3067\u6d3b\u7528\u3059\u308b\u305f\u3081\u306e\u91cd\u8981\u306a\u30dd\u30a4\u30f3\u30c8<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-120\">\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\u88c5\u9078\u629e\u306e\u6307\u91dd<\/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-117\">\n<li><strong>\u4e00\u822c\u7684\u306a\u7528\u9014<\/strong>\uff1a <code>HashMap<\/code>\u3092\u57fa\u672c\u7684\u306a\u9078\u629e\u80a2\u3068\u3057\u3066\u8003\u3048\u308b<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-118\">\n<li><strong>\u9806\u5e8f\u7ba1\u7406\u304c\u5fc5\u8981<\/strong>\uff1a <code>LinkedHashMap<\/code>\u3084<code>TreeMap<\/code>\u3092\u9078\u629e<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-119\">\n<li><strong>\u30de\u30eb\u30c1\u30b9\u30ec\u30c3\u30c9\u74b0\u5883<\/strong>\uff1a <code>ConcurrentHashMap<\/code>\u3092\u6d3b\u7528<\/li>\n<\/div>\n\n\n<li><strong>\u5927\u91cf\u30c7\u30fc\u30bf\u51e6\u7406<\/strong>\uff1a \u521d\u671f\u5bb9\u91cf\u306e\u9069\u5207\u306a\u8a2d\u5b9a\u3068\u30ed\u30fc\u30c9\u30d5\u30a1\u30af\u30bf\u30fc\u306e\u8abf\u6574\u3092\u5fd8\u308c\u305a\u306b<\/li>\n<\/ul>\n<\/div><\/div>\n<\/div>\n\n<div id=\"sgb-css-id-124\">\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\u6700\u9069\u5316\u306e\u30ad\u30fc\u30dd\u30a4\u30f3\u30c8<\/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-121\">\n<li>\u30ad\u30fc\u306e\u8a2d\u8a08\u3092\u614e\u91cd\u306b\u884c\u3044\u3001<code>equals()<\/code>\u3068<code>hashCode()<\/code>\u3092\u9069\u5207\u306b\u5b9f\u88c5\u3059\u308b<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-122\">\n<li>\u60f3\u5b9a\u30c7\u30fc\u30bf\u91cf\u306b\u57fa\u3065\u3044\u3066\u9069\u5207\u306a\u521d\u671f\u5bb9\u91cf\u3092\u8a2d\u5b9a\u3059\u308b<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-123\">\n<li>\u7528\u9014\u306b\u5fdc\u3058\u3066\u9069\u5207\u306aMap\u5b9f\u88c5\u3092\u9078\u629e\u3059\u308b<\/li>\n<\/div>\n\n\n<li>\u5fc5\u8981\u306b\u5fdc\u3058\u3066\u30ab\u30b9\u30bf\u30e0\u30ad\u30fc\u30af\u30e9\u30b9\u3092\u5b9f\u88c5\u3059\u308b<\/li>\n<\/ol>\n<\/div><\/div>\n<\/div>\n\n<div id=\"sgb-css-id-128\">\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\">\u958b\u767a\u73fe\u5834\u3067\u306e\u5b9f\u8df5\u7684\u306aTips<\/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-125\">\n<li>\u30e1\u30e2\u30ea\u30ea\u30fc\u30af\u3092\u9632\u3050\u305f\u3081\u3001\u30ad\u30e3\u30c3\u30b7\u30e5\u306b\u306f<code>WeakHashMap<\/code>\u3084<code>LinkedHashMap<\/code>\u306e\u6d3b\u7528\u3092\u691c\u8a0e\u3059\u308b<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-126\">\n<li>\u30de\u30eb\u30c1\u30b9\u30ec\u30c3\u30c9\u74b0\u5883\u3067\u306f\u5fc5\u305a\u9069\u5207\u306a\u540c\u671f\u5316\u3092\u884c\u3046<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-127\">\n<li>\u30d0\u30eb\u30af\u64cd\u4f5c\u6642\u306f<code>putAll()<\/code>\u3084<code>Stream API<\/code>\u3092\u6d3b\u7528\u3059\u308b<\/li>\n<\/div>\n\n\n<li>\u5927\u898f\u6a21\u30b7\u30b9\u30c6\u30e0\u3067\u306f\u30e2\u30cb\u30bf\u30ea\u30f3\u30b0\u3068\u9069\u5207\u306a\u30af\u30ea\u30fc\u30f3\u30a2\u30c3\u30d7\u3092\u5b9f\u88c5\u3059\u308b<\/li>\n<\/ul>\n<\/div><\/div>\n<\/div>\n\n<div id=\"sgb-css-id-129\">\n<h4 class=\"wp-block-heading\" id=\"i-62\">2. \u4eca\u5f8c\u306e\u5b66\u7fd2\u306e\u65b9\u5411\u6027<\/h4>\n<\/div>\n\n<div id=\"sgb-css-id-130\">\n<p>\u30001. <strong>\u57fa\u790e\u306e\u5f37\u5316<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-131\">\n<p>\u3000\u3000\u25cf Java Collections Framework\u5168\u4f53\u306e\u7406\u89e3\u3092\u6df1\u3081\u308b<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-132\">\n<p>\u3000\u3000\u25cf \u5404Map\u5b9f\u88c5\u306e\u7279\u5fb4\u3092\u3088\u308a\u8a73\u3057\u304f\u5b66\u3076<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-133\">\n<p>\u30002. <strong>\u5fdc\u7528\u529b\u306e\u5411\u4e0a<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-134\">\n<p>\u3000\u3000\u25cf \u30c7\u30b6\u30a4\u30f3\u30d1\u30bf\u30fc\u30f3\u3068Map\u306e\u7d44\u307f\u5408\u308f\u305b\u3092\u5b66\u3076<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-135\">\n<p>\u3000\u3000\u25cf \u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u30c1\u30e5\u30fc\u30cb\u30f3\u30b0\u306e\u5b9f\u8df5<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-136\">\n<p>\u3000\u3000\u25cf \u30de\u30eb\u30c1\u30b9\u30ec\u30c3\u30c9\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u306e\u6df1\u3044\u7406\u89e3<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-137\">\n<p>\u30003. <strong>\u6700\u65b0\u52d5\u5411\u306e\u30ad\u30e3\u30c3\u30c1\u30a2\u30c3\u30d7<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-138\">\n<p>\u3000\u3000\u25cf Java \u306e\u65b0\u30d0\u30fc\u30b8\u30e7\u30f3\u3067\u306e\u6a5f\u80fd\u8ffd\u52a0\u3092\u78ba\u8a8d<\/p>\n<\/div>\n\n\n<p>\u3000\u3000\u25cf \u65b0\u3057\u3044\u5b9f\u88c5\u30d1\u30bf\u30fc\u30f3\u3084\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\u306e\u5b66\u7fd2<\/p>\n\n\n<div 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