{"id":208,"date":"2024-10-01T12:00:00","date_gmt":"2024-10-01T03:00:00","guid":{"rendered":"https:\/\/dexall.co.jp\/articles\/?p=208"},"modified":"2025-03-24T08:54:58","modified_gmt":"2025-03-23T23:54:58","slug":"%e3%80%90%e5%ae%8c%e5%85%a8%e3%82%ac%e3%82%a4%e3%83%89%e3%80%91java-equals%e3%83%a1%e3%82%bd%e3%83%83%e3%83%89%ef%bc%9a%e6%ad%a3%e7%a2%ba%e3%81%aa%e6%af%94%e8%bc%83%e3%81%a8%e5%8a%b9%e7%8e%87","status":"publish","type":"post","link":"https:\/\/dexall.co.jp\/articles\/?p=208","title":{"rendered":"\u3010\u5b8c\u5168\u30ac\u30a4\u30c9\u3011Java equals()\u30e1\u30bd\u30c3\u30c9\uff1a\u6b63\u78ba\u306a\u6bd4\u8f03\u3068\u52b9\u7387\u7684\u306a\u5b9f\u88c5\u306e\u79d8\u8a23"},"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\">1. Java equals()\u30e1\u30bd\u30c3\u30c9\u306e\u57fa\u790e\u77e5\u8b58<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-2\">equals()\u30e1\u30bd\u30c3\u30c9\u3068\u306f\uff1f\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u6bd4\u8f03\u306e\u8981<\/a>      <\/li>      <li>        <a href=\"#i-3\">\u306a\u305c\u300c==\u300d\u6f14\u7b97\u5b50\u3067\u306f\u306a\u304fequals()\u3092\u4f7f\u3046\u3079\u304d\u304b<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-4\">equals()\u5b9f\u88c5\u6642\u306e\u6ce8\u610f\u70b9\uff1anull\u5b89\u5168\u6027\u3068\u4e00\u8cab\u6027<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-5\">2. String \u30af\u30e9\u30b9\u306b\u304a\u3051\u308b equals() \u306e\u4f7f\u7528\u6cd5<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-6\">\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u6b63\u3057\u3044\u65b9\u6cd5\uff1aequals()  vs  ==<\/a>      <\/li>      <li>        <a href=\"#i-7\">\u5927\u6587\u5b57\u5c0f\u6587\u5b57\u3092\u533a\u5225\u3057\u306a\u3044\u6bd4\u8f03\uff1aequalsIgnoreCase()<\/a>      <\/li>      <li>        <a href=\"#i-8\">null \u5b89\u5168\u6027\u3068\u7a7a\u6587\u5b57\u5217\u306e\u53d6\u308a\u6271\u3044<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-9\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3068 String.intern()<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-10\">3. \u30ab\u30b9\u30bf\u30e0\u30af\u30e9\u30b9\u3067\u306e equals() \u30e1\u30bd\u30c3\u30c9\u306e\u5b9f\u88c5<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-11\">equals()\u30e1\u30bd\u30c3\u30c9\u3092\u30aa\u30fc\u30d0\u30fc\u30e9\u30a4\u30c9\u3059\u308b5\u3064\u306e\u30b9\u30c6\u30c3\u30d7<\/a>      <\/li>      <li>        <a href=\"#i-12\">equals()\u5b9f\u88c5\u6642\u306e\u6ce8\u610f\u70b9\uff1anull\u5b89\u5168\u6027\u3068\u4e00\u8cab\u6027<\/a>      <\/li>      <li>        <a href=\"#i-13\">\u7d99\u627f\u6642\u306eequals()\u5b9f\u88c5\u306e\u843d\u3068\u3057\u7a74<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-14\">IDE\u6a5f\u80fd\u3068\u30e9\u30a4\u30d6\u30e9\u30ea\u306e\u6d3b\u7528<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-15\">4. equals() \u3068 hashCode() \u306e\u6df1\u3044\u95a2\u4fc2<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-16\">\u306a\u305cequals()\u3092\u30aa\u30fc\u30d0\u30fc\u30e9\u30a4\u30c9\u3057\u305f\u3089hashCode()\u3082\u5fc5\u8981\u304b<\/a>      <\/li>      <li>        <a href=\"#i-17\">\u52b9\u7387\u7684\u306ahashCode()\u306e\u5b9f\u88c5\u30c6\u30af\u30cb\u30c3\u30af<\/a>      <\/li>      <li>        <a href=\"#i-18\">hashCode()\u5b9f\u88c5\u6642\u306e\u6ce8\u610f\u70b9<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-19\">\u307e\u3068\u3081<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-20\">5. Java 7\u4ee5\u964d\u306e equals() \u5b9f\u88c5\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-21\">Objects.equals()\u306e\u6d3b\u7528\uff1anull\u5b89\u5168\u6027\u306e\u5411\u4e0a<\/a>      <\/li>      <li>        <a href=\"#i-22\">\u52b9\u7387\u7684\u306ahashCode()\u5b9f\u88c5\uff1aObjects.hash()<\/a>      <\/li>      <li>        <a href=\"#i-23\">Java 7\u306eDiamond Operator (&lt;&gt;)<\/a>      <\/li>      <li>        <a href=\"#i-24\">Apache Commons Lang\uff1aEqualsBuilder for \u7c21\u6f54\u306aequals()<\/a>      <\/li>      <li>        <a href=\"#i-25\">Java 8\u4ee5\u964d\uff1aOptional \u30af\u30e9\u30b9\u306e\u6d3b\u7528<\/a>      <\/li>      <li>        <a href=\"#i-26\">Java 9\u4ee5\u964d\uff1a\u4e0d\u5909\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u30d5\u30a1\u30af\u30c8\u30ea\u30e1\u30bd\u30c3\u30c9<\/a>      <\/li>      <li>        <a href=\"#i-27\">IDE\u306e\u30b5\u30dd\u30fc\u30c8\u6d3b\u7528<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-28\">\u307e\u3068\u3081<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-29\">6. equals()\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3068\u6700\u9069\u5316\u30c6\u30af\u30cb\u30c3\u30af<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-30\">\u65e9\u671f\u30ea\u30bf\u30fc\u30f3\u3067\u52b9\u7387\u30a2\u30c3\u30d7\uff1aequals()\u306e\u6700\u9069\u5316\u6226\u7565<\/a>      <\/li>      <li>        <a href=\"#i-31\">\u30d5\u30a3\u30fc\u30eb\u30c9\u6bd4\u8f03\u306e\u9806\u5e8f\u6700\u9069\u5316<\/a>      <\/li>      <li>        <a href=\"#i-32\">hashCode()\u306e\u30ad\u30e3\u30c3\u30b7\u30e5\u6d3b\u7528<\/a>      <\/li>      <li>        <a href=\"#i-33\">\u5927\u898f\u6a21\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3067\u306eequals()\u3068\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u8003\u5bdf<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-34\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3068\u53ef\u8aad\u6027\u306e\u30d0\u30e9\u30f3\u30b9<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-35\">7. \u3088\u304f\u3042\u308b equals() \u306e\u5b9f\u88c5\u30df\u30b9\u3068\u305d\u306e\u56de\u907f\u65b9\u6cd5<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-36\">\u5bfe\u79f0\u6027\u9055\u53cd\u3092\u907f\u3051\u308b\uff1a\u53cc\u65b9\u5411\u306e\u7b49\u4fa1\u6027\u3092\u78ba\u4fdd<\/a>      <\/li>      <li>        <a href=\"#i-37\">\u63a8\u79fb\u6027\u3092\u4fdd\u3064\uff1a\u7d99\u627f\u6642\u306eequals()\u5b9f\u88c5\u306e\u843d\u3068\u3057\u7a74<\/a>      <\/li>      <li>        <a href=\"#i-38\">null \u5b89\u5168\u6027\u3068\u4e00\u8cab\u6027\u3092\u4fdd\u3064<\/a>      <\/li>      <li>        <a href=\"#i-39\">\u6d6e\u52d5\u5c0f\u6570\u70b9\u6570\u306e\u6bd4\u8f03\u306b\u304a\u3051\u308b\u6ce8\u610f\u70b9<\/a>      <\/li>      <li>        <a href=\"#i-40\">\u914d\u5217\u3068\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u306e\u6bd4\u8f03<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-41\">\u5b9f\u88c5\u30df\u30b9\u3068\u305d\u306e\u56de\u907f\u306e\u307e\u3068\u3081<\/a>      <\/li>    <\/ul>  <\/li>  <li class=\"last\">    <a href=\"#i-42\">8. \u307e\u3068\u3081\uff1a\u5805\u7262\u306aJava\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u958b\u767a\u306b\u5411\u3051\u3066<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-43\">equals()\u30de\u30b9\u30bf\u30fc\u3078\u306e\u9053\uff1a\u6b21\u306e\u30b9\u30c6\u30c3\u30d7\u3068\u5b66\u7fd2\u30ea\u30bd\u30fc\u30b9<\/a>      <\/li>      <li>        <a href=\"#i-44\">\u5c06\u6765\u3092\u898b\u636e\u3048\u3066<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-45\">\u6700\u5f8c\u306b<\/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\">\u306f\u3058\u3081\u306b<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-2\">\n<p>Java\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u306b\u304a\u3044\u3066\u3001\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u7b49\u4fa1\u6027\u3092\u6b63\u78ba\u306b\u5224\u65ad\u3059\u308b\u3053\u3068\u306f\u6975\u3081\u3066\u91cd\u8981\u3067\u3059\u3002\u305d\u306e\u4e2d\u5fc3\u7684\u306a\u5f79\u5272\u3092\u679c\u305f\u3059\u306e\u304c<code>equals()<\/code>\u30e1\u30bd\u30c3\u30c9\u3067\u3059\u3002\u300cjava equals\u300d\u3068\u3044\u3046\u8a00\u8449\u3092\u805e\u3044\u305f\u3053\u3068\u304c\u3042\u308b\u65b9\u3082\u591a\u3044\u3067\u3057\u3087\u3046\u3002\u3057\u304b\u3057\u3001\u305d\u306e\u771f\u306e\u529b\u3068\u9069\u5207\u306a\u4f7f\u3044\u65b9\u3092\u7406\u89e3\u3057\u3066\u3044\u308b\u958b\u767a\u8005\u306f\u610f\u5916\u3068\u5c11\u306a\u3044\u306e\u304c\u73fe\u72b6\u3067\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-3\">\n<p>\u672c\u8a18\u4e8b\u3067\u306f\u3001Java\u8a00\u8a9e\u306e\u6838\u5fc3\u90e8\u5206\u3068\u3082\u8a00\u3048\u308b<code>equals()<\/code>\u30e1\u30bd\u30c3\u30c9\u306b\u3064\u3044\u3066\u3001\u57fa\u790e\u304b\u3089\u5fdc\u7528\u307e\u3067\u5fb9\u5e95\u7684\u306b\u89e3\u8aac\u3057\u307e\u3059\u3002\u5177\u4f53\u7684\u306b\u4ee5\u4e0b\u306e\u30c8\u30d4\u30c3\u30af\u3092\u30ab\u30d0\u30fc\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<ul class=\"wp-block-list is-style-sango-list-simple\"><div id=\"sgb-css-id-4\">\n<li><code>equals()<\/code>\u30e1\u30bd\u30c3\u30c9\u306e\u57fa\u672c\u7684\u306a\u6982\u5ff5\u3068\u4f7f\u3044\u65b9<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-5\">\n<li>String\u30af\u30e9\u30b9\u3067\u306e\u6b63\u3057\u3044\u6bd4\u8f03\u65b9\u6cd5<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-6\">\n<li>\u30ab\u30b9\u30bf\u30e0\u30af\u30e9\u30b9\u3067\u306e\u52b9\u679c\u7684\u306a\u5b9f\u88c5\u30c6\u30af\u30cb\u30c3\u30af<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-7\">\n<li><code>hashCode()<\/code>\u30e1\u30bd\u30c3\u30c9\u3068\u306e\u6df1\u3044\u95a2\u4fc2<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-8\">\n<li>Java 7\u4ee5\u964d\u306e\u6700\u65b0\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-9\">\n<li>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316\u306e\u79d8\u8a23<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-10\">\n<li>\u3088\u304f\u3042\u308b\u5b9f\u88c5\u30df\u30b9\u3068\u305d\u306e\u56de\u907f\u65b9\u6cd5<\/li>\n<\/div><\/ul>\n\n\n<div id=\"sgb-css-id-11\">\n<p>\u3053\u306e\u8a18\u4e8b\u3092\u8aad\u307f\u7d42\u3048\u308b\u3053\u308d\u306b\u306f\u3001\u3042\u306a\u305f\u306f<code>equals()<\/code>\u30e1\u30bd\u30c3\u30c9\u306e\u30de\u30b9\u30bf\u30fc\u3068\u3057\u3066\u3001\u3088\u308a\u5805\u7262\u3067\u52b9\u7387\u7684\u306aJava\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3092\u958b\u767a\u3067\u304d\u308b\u3088\u3046\u306b\u306a\u3063\u3066\u3044\u308b\u3067\u3057\u3087\u3046\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-12\">\n<h2 class=\"wp-block-heading\" id=\"i-1\">1. Java equals()\u30e1\u30bd\u30c3\u30c9\u306e\u57fa\u790e\u77e5\u8b58<\/h2>\n<\/div>\n\n\n<h3 class=\"wp-block-heading\" id=\"i-2\">equals()\u30e1\u30bd\u30c3\u30c9\u3068\u306f\uff1f\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u6bd4\u8f03\u306e\u8981<\/h3>\n\n\n<div id=\"sgb-css-id-13\">\n<p><code>equals()<\/code>\u30e1\u30bd\u30c3\u30c9\u306f\u3001Java\u306b\u304a\u3051\u308b\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u6bd4\u8f03\u306e\u4e2d\u5fc3\u7684\u306a\u5f79\u5272\u3092\u679c\u305f\u3057\u307e\u3059\u3002\u3053\u306e\u30e1\u30bd\u30c3\u30c9\u306f<code>Object<\/code>\u30af\u30e9\u30b9\u3067\u5b9a\u7fa9\u3055\u308c\u3066\u304a\u308a\u3001\u3059\u3079\u3066\u306eJava\u30af\u30e9\u30b9\u304c\u30c7\u30d5\u30a9\u30eb\u30c8\u3067\u7d99\u627f\u3057\u3066\u3044\u307e\u3059\u3002\u305d\u306e\u4e3b\u306a\u76ee\u7684\u306f\u30012\u3064\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u304c\u300c\u7b49\u4fa1\u300d\u3067\u3042\u308b\u304b\u3069\u3046\u304b\u3092\u5224\u65ad\u3059\u308b\u3053\u3068\u3067\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-14\">\n<p><code>Object<\/code>\u30af\u30e9\u30b9\u306b\u304a\u3051\u308b<code>equals()<\/code>\u30e1\u30bd\u30c3\u30c9\u306e\u30c7\u30d5\u30a9\u30eb\u30c8\u5b9f\u88c5\u306f\u4ee5\u4e0b\u306e\u901a\u308a\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 boolean equals(Object obj) {\n    return (this == obj);\n}<\/pre>\n\n\n<div id=\"sgb-css-id-15\">\n<p>\u3053\u306e\u30c7\u30d5\u30a9\u30eb\u30c8\u5b9f\u88c5\u306f\u5358\u306b\u53c2\u7167\u306e\u540c\u4e00\u6027\u3092\u30c1\u30a7\u30c3\u30af\u3057\u3066\u3044\u308b\u3060\u3051\u3067\u3001\u591a\u304f\u306e\u5834\u5408\u3001\u30aa\u30fc\u30d0\u30fc\u30e9\u30a4\u30c9\u3057\u3066\u72ec\u81ea\u306e\u7b49\u4fa1\u6027\u306e\u5b9a\u7fa9\u3092\u63d0\u4f9b\u3059\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-16\">\n<h3 class=\"wp-block-heading\" id=\"i-3\">\u306a\u305c\u300c==\u300d\u6f14\u7b97\u5b50\u3067\u306f\u306a\u304fequals()\u3092\u4f7f\u3046\u3079\u304d\u304b<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-17\">\n<p>\u300c==\u300d\u6f14\u7b97\u6f14\u7b97\u5b50\u3068<code>equals()<\/code>\u30e1\u30bd\u30c3\u30c9\u306e\u9055\u3044\u306f\u3001Java\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u306b\u304a\u3044\u3066\u975e\u5e38\u306b\u91cd\u8981\u3067\u3059\u3002\u4ee5\u4e0b\u306b\u4e3b\u306a\u9055\u3044\u3092\u793a\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<ol class=\"wp-block-list is-style-sango-list-simple\">\n<li>\u53c2\u7167\u306e\u6bd4\u8f03 vs \u5185\u5bb9\u306e\u6bd4\u8f03\n<ul class=\"wp-block-list is-style-sango-list-simple\"><div id=\"sgb-css-id-18\">\n<li>\u300c==\u300d\u6f14\u7b97\u5b50\uff1a\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u53c2\u7167\uff08\u30e1\u30e2\u30ea\u30a2\u30c9\u30ec\u30b9\uff09\u3092\u6bd4\u8f03<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-19\">\n<li><code>equals()<\/code>\u30e1\u30bd\u30c3\u30c9\uff1a\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u5185\u5bb9\u3092\u6bd4\u8f03\uff08\u9069\u5207\u306b\u30aa\u30fc\u30d0\u30fc\u30e9\u30a4\u30c9\u3055\u308c\u3066\u3044\u308b\u5834\u5408\uff09<\/li>\n<\/div><\/ul>\n<\/li>\n\n\n\n<li>\u30d7\u30ea\u30df\u30c6\u30a3\u30d6\u578b\u3068\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u578b\u3067\u306e\u52d5\u4f5c[\n<ul class=\"wp-block-list is-style-sango-list-simple\"><div id=\"sgb-css-id-20\">\n<li>\u30d7\u30ea\u30df\u30c6\u30a3\u30d6\u578b\uff1a\u300c==\u300d\u6f14\u7b97\u5b50\u3067\u5024\u3092\u76f4\u63a5\u6bd4\u8f03<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-21\">\n<li>\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u578b\uff1a<code>equals()<\/code>\u30e1\u30bd\u30c3\u30c9\u3067\u5185\u5bb9\u3092\u6bd4\u8f03<\/li>\n<\/div><\/ul>\n<\/li>\n<\/ol>\n\n\n<div id=\"sgb-css-id-22\">\n<p>\u4ee5\u4e0b\u306e\u4f8b\u3067\u3001\u3053\u306e\u9055\u3044\u3092\u660e\u78ba\u306b\u793a\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=\"\">String str1 = new String(\"Hello\");\nString str2 = new String(\"Hello\");\n\nSystem.out.println(str1 == str2);        \/\/ false\uff08\u7570\u306a\u308b\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u53c2\u7167\uff09\nSystem.out.println(str1.equals(str2));   \/\/ true\uff08\u5185\u5bb9\u304c\u540c\u3058\uff09\n\nInteger num1 = 128;\nInteger num2 = 128;\n\nSystem.out.println(num1 == num2);        \/\/ false\uff08-128\u304b\u3089127\u306e\u7bc4\u56f2\u5916\uff09\nSystem.out.println(num1.equals(num2));   \/\/ true\uff08\u5024\u304c\u540c\u3058\uff09<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-4\">equals()\u5b9f\u88c5\u6642\u306e\u6ce8\u610f\u70b9\uff1anull\u5b89\u5168\u6027\u3068\u4e00\u8cab\u6027<\/h3>\n\n\n<div id=\"sgb-css-id-23\">\n<p><code>equals()<\/code>\u30e1\u30bd\u30c3\u30c9\u3092\u5b9f\u88c5\u3059\u308b\u969b\u306f\u3001\u4ee5\u4e0b\u306e\u70b9\u306b\u6ce8\u610f\u304c\u5fc5\u8981\u3067\u3059\u3002<\/p>\n<\/div>\n\n\n<ol class=\"wp-block-list is-style-sango-list-simple\"><div id=\"sgb-css-id-24\">\n<li>null\u5b89\u5168\u6027\uff1aNullPointerException\u3092\u907f\u3051\u308b\u305f\u3081\u3001\u6bd4\u8f03\u5bfe\u8c61\u304cnull\u3067\u306a\u3044\u3053\u3068\u3092\u78ba\u8a8d\u3059\u308b<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-25\">\n<li>\u4e00\u8cab\u6027\uff1a\u540c\u3058\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306b\u5bfe\u3057\u3066\u5e38\u306b\u540c\u3058\u7d50\u679c\u3092\u8fd4\u3059<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-26\">\n<li>\u5bfe\u79f0\u6027\uff1ax.equals(y) \u304c true \u306a\u3089\u3001y.equals(x) \u3082 true \u306b\u306a\u308b\u3088\u3046\u306b\u3059\u308b<\/li>\n<\/div><\/ol>\n\n\n<div id=\"sgb-css-id-27\">\n<p>\u4ee5\u4e0b\u306f\u3001\u3053\u308c\u3089\u306e\u6ce8\u610f\u70b9\u3092\u8003\u616e\u3057\u305f<code>equals()<\/code>\u30e1\u30bd\u30c3\u30c9\u306e\u5b9f\u88c5\u4f8b\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 Person {\n    private String name;\n    private int age;\n\n    \/\/ \u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u3001\u30b2\u30c3\u30bf\u30fc\u3001\u30bb\u30c3\u30bf\u30fc\u306f\u7701\u7565\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        Person person = (Person) obj;\n        return age == person.age &amp;&amp; Objects.equals(name, person.name);\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-28\">\n<p>\u3053\u306e\u5b9f\u88c5\u3067\u306f\u3001null\u5b89\u5168\u6027\u3001\u4e00\u8cab\u6027\u3001\u5bfe\u79f0\u6027\u3092\u78ba\u4fdd\u3057\u3064\u3064\u3001\u540d\u524d\u3068\u5e74\u9f62\u304c\u540c\u3058\u3067\u3042\u308c\u3070\u7b49\u4fa1\u3068\u307f\u306a\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-29\">\n<p><code>equals()<\/code>\u30e1\u30bd\u30c3\u30c9\u3092\u6b63\u3057\u304f\u5b9f\u88c5\u3059\u308b\u3053\u3068\u3067\u3001\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u306e\u64cd\u4f5c\u3084\u6587\u5b57\u5217\u6bd4\u8f03\u306a\u3069\u3001\u591a\u304f\u306e\u5834\u9762\u3067\u4fe1\u983c\u6027\u306e\u9ad8\u3044\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u6bd4\u8f03\u304c\u53ef\u80fd\u306b\u306a\u308a\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001String \u30af\u30e9\u30b9\u306b\u304a\u3051\u308b<code>equals()<\/code>\u306e\u4f7f\u7528\u6cd5\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-30\">\n<h2 class=\"wp-block-heading\" id=\"i-5\">2. String \u30af\u30e9\u30b9\u306b\u304a\u3051\u308b equals() \u306e\u4f7f\u7528\u6cd5<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-31\">\n<h3 class=\"wp-block-heading\" id=\"i-6\">\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u6b63\u3057\u3044\u65b9\u6cd5\uff1aequals()  vs  ==<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-32\">\n<p>String \u30af\u30e9\u30b9\u306f Java \u3067\u6700\u3082\u983b\u7e41\u306b\u4f7f\u7528\u3055\u308c\u308b\u30af\u30e9\u30b9\u306e\u4e00\u3064\u3067\u3042\u308a\u3001\u305d\u306e\u6bd4\u8f03\u64cd\u4f5c\u306f\u591a\u304f\u306e\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3067\u91cd\u8981\u306a\u5f79\u5272\u3092\u679c\u305f\u3057\u307e\u3059\u3002String \u30af\u30e9\u30b9\u3067\u306f\u3001<code>equals()<\/code> \u30e1\u30bd\u30c3\u30c9\u304c\u9069\u5207\u306b\u30aa\u30fc\u30d0\u30fc\u30e9\u30a4\u30c9\u3055\u308c\u3066\u304a\u308a\u3001\u6587\u5b57\u5217\u306e\u5185\u5bb9\u3092\u6bd4\u8f03\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-33\">\n<p>\u4ee5\u4e0b\u306b\u3001<code>equals()<\/code> \u3068 <code>==<\/code> \u306e\u9055\u3044\u3092\u793a\u3059\u5177\u4f53\u4f8b\u3092\u898b\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=\"\">String str1 = \"Hello\";\nString str2 = \"Hello\";\nString str3 = new String(\"Hello\");\n\nSystem.out.println(str1 == str2);        \/\/ true\uff08\u540c\u3058\u6587\u5b57\u5217\u30ea\u30c6\u30e9\u30eb\u3092\u53c2\u7167\uff09\nSystem.out.println(str1 == str3);        \/\/ false\uff08\u7570\u306a\u308b\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\uff09\nSystem.out.println(str1.equals(str2));   \/\/ true\uff08\u5185\u5bb9\u304c\u540c\u3058\uff09\nSystem.out.println(str1.equals(str3));   \/\/ true\uff08\u5185\u5bb9\u304c\u540c\u3058\uff09<\/pre>\n\n\n<div id=\"sgb-css-id-34\">\n<p>\u3053\u306e\u4f8b\u304b\u3089\u5206\u304b\u308b\u3088\u3046\u306b\u3001<code>==<\/code> \u306f\u53c2\u7167\u306e\u540c\u4e00\u6027\u3092\u6bd4\u8f03\u3057\u3001<code>equals()<\/code> \u306f\u6587\u5b57\u5217\u306e\u5185\u5bb9\u3092\u6bd4\u8f03\u3057\u307e\u3059\u3002\u6587\u5b57\u5217\u30ea\u30c6\u30e9\u30eb\u306f Java \u306e\u6587\u5b57\u5217\u30d7\u30fc\u30eb\u306b\u683c\u7d0d\u3055\u308c\u308b\u305f\u3081\u3001\u540c\u3058\u30ea\u30c6\u30e9\u30eb\u306f\u540c\u3058\u53c2\u7167\u3092\u6301\u3061\u307e\u3059\u304c\u3001<code>new String()<\/code> \u3067\u751f\u6210\u3055\u308c\u305f\u6587\u5b57\u5217\u306f\u65b0\u3057\u3044\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3068\u306a\u308a\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-35\">\n<h3 class=\"wp-block-heading\" id=\"i-7\">\u5927\u6587\u5b57\u5c0f\u6587\u5b57\u3092\u533a\u5225\u3057\u306a\u3044\u6bd4\u8f03\uff1aequalsIgnoreCase()<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-36\">\n<p>\u6587\u5b57\u5217\u3092\u5927\u6587\u5b57\u5c0f\u6587\u5b57\u3092\u533a\u5225\u305b\u305a\u306b\u6bd4\u8f03\u3057\u305f\u3044\u5834\u5408\u3001<code>equalsIgnoreCase()<\/code> \u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u7528\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=\"\">String str1 = \"hello\";\nString str2 = \"HELLO\";\n\nSystem.out.println(str1.equals(str2));           \/\/ false\nSystem.out.println(str1.equalsIgnoreCase(str2)); \/\/ true<\/pre>\n\n\n<div id=\"sgb-css-id-37\">\n<p><code>equalsIgnoreCase()<\/code> \u306f\u5185\u90e8\u3067\u6587\u5b57\u3092\u5927\u6587\u5b57\u306b\u5909\u63db\u3057\u3066\u6bd4\u8f03\u3059\u308b\u305f\u3081\u3001\u82e5\u5e72\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u30aa\u30fc\u30d0\u30fc\u30d8\u30c3\u30c9\u304c\u3042\u308a\u307e\u3059\u304c\u3001\u5927\u6587\u5b57\u5c0f\u6587\u5b57\u3092\u533a\u5225\u3057\u306a\u3044\u6bd4\u8f03\u304c\u5fc5\u8981\u306a\u5834\u5408\u306b\u975e\u5e38\u306b\u4fbf\u5229\u3067\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-38\">\n<h3 class=\"wp-block-heading\" id=\"i-8\">null \u5b89\u5168\u6027\u3068\u7a7a\u6587\u5b57\u5217\u306e\u53d6\u308a\u6271\u3044<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-39\">\n<p>\u6587\u5b57\u5217\u6bd4\u8f03\u3092\u884c\u3046\u969b\u306f\u3001null \u5024\u3068\u7a7a\u6587\u5b57\u5217\u306e\u53d6\u308a\u6271\u3044\u306b\u6ce8\u610f\u304c\u5fc5\u8981\u3067\u3059\u3002\u4ee5\u4e0b\u306b\u5b89\u5168\u306a\u6bd4\u8f03\u65b9\u6cd5\u3092\u793a\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=\"\">String str1 = null;\nString str2 = \"\";\n\n\/\/ null \u5b89\u5168\u306a\u6bd4\u8f03\nSystem.out.println(Objects.equals(str1, str2)); \/\/ false\n\n\/\/ \u7a7a\u6587\u5b57\u5217\u306e\u30c1\u30a7\u30c3\u30af\nSystem.out.println(str2.isEmpty()); \/\/ true\n\n\/\/ Java 11\u4ee5\u964d\uff1a\u7a7a\u767d\u6587\u5b57\u306e\u307f\u306e\u6587\u5b57\u5217\u3082\u30c1\u30a7\u30c3\u30af\nSystem.out.println(\"  \".isBlank()); \/\/ true<\/pre>\n\n\n<div id=\"sgb-css-id-40\">\n<p><code>Objects.equals()<\/code> \u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u3067\u3001null \u5024\u306b\u3088\u308b NullPointerException \u3092\u56de\u907f\u3067\u304d\u307e\u3059\u3002\u307e\u305f\u3001<code>isEmpty()<\/code> \u3068 <code>isBlank()<\/code> (Java 11\u4ee5\u964d) \u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u7a7a\u6587\u5b57\u5217\u3084\u7a7a\u767d\u6587\u5b57\u306e\u307f\u306e\u6587\u5b57\u5217\u3092\u9069\u5207\u306b\u51e6\u7406\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-41\">\n<h3 class=\"wp-block-heading\" id=\"i-9\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3068 String.intern()<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-42\">\n<p>\u5927\u898f\u6a21\u306a\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3067\u983b\u7e41\u306b\u6587\u5b57\u5217\u6bd4\u8f03\u3092\u884c\u3046\u5834\u5408\u3001<code>String.intern()<\/code> \u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u3067\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u5411\u4e0a\u3055\u305b\u308b\u3053\u3068\u304c\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=\"\">String str1 = new String(\"Hello\").intern();\nString str2 = \"Hello\";\n\nSystem.out.println(str1 == str2); \/\/ true<\/pre>\n\n\n<div id=\"sgb-css-id-43\">\n<p><code>intern()<\/code> \u30e1\u30bd\u30c3\u30c9\u306f\u6587\u5b57\u5217\u3092String \u30d7\u30fc\u30eb\u306b\u8ffd\u52a0\u3057\u3001\u30d7\u30fc\u30eb\u5185\u306e\u540c\u3058\u5185\u5bb9\u306e\u6587\u5b57\u5217\u3078\u306e\u53c2\u7167\u3092\u8fd4\u3057\u307e\u3059\u3002\u3053\u308c\u306b\u3088\u308a\u3001<code>==<\/code> \u6f14\u7b97\u5b50\u3067\u306e\u6bd4\u8f03\u304c\u53ef\u80fd\u306b\u306a\u308a\u3001<code>equals()<\/code> \u3088\u308a\u3082\u9ad8\u901f\u306b\u6bd4\u8f03\u3067\u304d\u307e\u3059\u3002\u305f\u3060\u3057\u3001<code>intern()<\/code> \u306e\u4f7f\u7528\u306f\u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u3068\u306e\u30c8\u30ec\u30fc\u30c9\u30aa\u30d5\u306b\u306a\u308b\u305f\u3081\u3001\u9069\u5207\u306a\u72b6\u6cc1\u3067\u306e\u307f\u4f7f\u7528\u3059\u308b\u3079\u304d\u3067\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-44\">\n<p>\u6587\u5b57\u5217\u6bd4\u8f03\u306f Java \u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u306e\u57fa\u672c\u7684\u304b\u3064\u91cd\u8981\u306a\u64cd\u4f5c\u3067\u3059\u3002\u9069\u5207\u306a\u65b9\u6cd5\u3092\u9078\u629e\u3057\u3001null \u5b89\u5168\u6027\u3092\u78ba\u4fdd\u3059\u308b\u3053\u3068\u3067\u3001\u30d0\u30b0\u306e\u5c11\u306a\u3044\u5805\u7262\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\u30ab\u30b9\u30bf\u30e0\u30af\u30e9\u30b9\u3067\u306e <code>equals()<\/code> \u30e1\u30bd\u30c3\u30c9\u306e\u5b9f\u88c5\u306b\u3064\u3044\u3066\u8a73\u3057\u304f\u898b\u3066\u3044\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-45\">\n<h2 class=\"wp-block-heading\" id=\"i-10\">3. \u30ab\u30b9\u30bf\u30e0\u30af\u30e9\u30b9\u3067\u306e equals() \u30e1\u30bd\u30c3\u30c9\u306e\u5b9f\u88c5<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-46\">\n<p>\u30ab\u30b9\u30bf\u30e0\u30af\u30e9\u30b9\u3092\u4f5c\u6210\u3059\u308b\u969b\u3001<code>equals()<\/code> \u30e1\u30bd\u30c3\u30c9\u3092\u9069\u5207\u306b\u30aa\u30fc\u30d0\u30fc\u30e9\u30a4\u30c9\u3059\u308b\u3053\u3068\u306f\u975e\u5e38\u306b\u91cd\u8981\u3067\u3059\u3002\u6b63\u3057\u304f\u5b9f\u88c5\u3055\u308c\u3066\u3044\u306a\u3044\u3068\u3001HashMap\u3084HashSet\u306a\u3069\u306e\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u3067\u4e88\u671f\u305b\u306c\u52d5\u4f5c\u3092\u5f15\u304d\u8d77\u3053\u3059\u53ef\u80fd\u6027\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-47\">\n<h3 class=\"wp-block-heading\" id=\"i-11\">equals()\u30e1\u30bd\u30c3\u30c9\u3092\u30aa\u30fc\u30d0\u30fc\u30e9\u30a4\u30c9\u3059\u308b5\u3064\u306e\u30b9\u30c6\u30c3\u30d7<\/h3>\n<\/div>\n\n\n<ol class=\"wp-block-list is-style-sango-list-simple\"><div id=\"sgb-css-id-48\">\n<li><strong>\u540c\u4e00\u6027\u30c1\u30a7\u30c3\u30af<\/strong>\uff1a <code>this == obj<\/code> \u3092\u4f7f\u7528\u3057\u3066\u3001\u6bd4\u8f03\u5bfe\u8c61\u304c\u81ea\u5206\u81ea\u8eab\u304b\u3069\u3046\u304b\u3092\u30c1\u30a7\u30c3\u30af\u3059\u308b\u3002<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-49\">\n<li><strong>null \u30c1\u30a7\u30c3\u30af<\/strong>\uff1a <code>obj == null<\/code> \u3092\u30c1\u30a7\u30c3\u30af\u3057\u3066\u3001null\u3068\u306e\u6bd4\u8f03\u3092\u9632\u3050\u3002<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-50\">\n<li><strong>\u578b\u30c1\u30a7\u30c3\u30af<\/strong>\uff1a <code>getClass() != obj.getClass()<\/code> \u3092\u4f7f\u7528\u3057\u3066\u3001\u6bd4\u8f03\u5bfe\u8c61\u304c\u540c\u3058\u30af\u30e9\u30b9\u304b\u3069\u3046\u304b\u3092\u78ba\u8a8d\u3059\u308b\u3002<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-51\">\n<li><strong>\u30ad\u30e3\u30b9\u30c8<\/strong>\uff1a \u6bd4\u8f03\u5bfe\u8c61\u3092\u9069\u5207\u306a\u578b\u306b\u30ad\u30e3\u30b9\u30c8\u3059\u308b\u3002<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-52\">\n<li><strong>\u30d5\u30a3\u30fc\u30eb\u30c9\u6bd4\u8f03<\/strong>\uff1a \u30af\u30e9\u30b9\u306e\u91cd\u8981\u306a\u30d5\u30a3\u30fc\u30eb\u30c9\u3092\u6bd4\u8f03\u3059\u308b\u3002<\/li>\n<\/div><\/ol>\n\n\n<div id=\"sgb-css-id-53\">\n<p>\u4ee5\u4e0b\u306b\u3001\u3053\u308c\u3089\u306e\u30b9\u30c6\u30c3\u30d7\u3092\u8e0f\u307e\u3048\u305f <code>equals()<\/code> \u30e1\u30bd\u30c3\u30c9\u306e\u5b9f\u88c5\u4f8b\u3092\u793a\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=\"\">public class Person {\n    private final String name;\n    private final int age;\n\n    \/\/ \u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u7b49\u306f\u7701\u7565\n\n    @Override\n    public boolean equals(Object obj) {\n        if (this == obj) return true;                       \/\/ \u540c\u4e00\u6027\u30c1\u30a7\u30c3\u30af\n        if (obj == null || getClass() != obj.getClass()) return false; \/\/ null \u30c1\u30a7\u30c3\u30af\u3068\u578b\u30c1\u30a7\u30c3\u30af\n        Person person = (Person) obj;                       \/\/ \u30ad\u30e3\u30b9\u30c8\n        return age == person.age &amp;&amp; Objects.equals(name, person.name); \/\/ \u30d5\u30a3\u30fc\u30eb\u30c9\u6bd4\u8f03\n    }\n\n    @Override\n    public int hashCode() {\n        return Objects.hash(name, age);\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-54\">\n<h3 class=\"wp-block-heading\" id=\"i-12\">equals()\u5b9f\u88c5\u6642\u306e\u6ce8\u610f\u70b9\uff1anull\u5b89\u5168\u6027\u3068\u4e00\u8cab\u6027<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-55\">\n<p><code>equals()<\/code> \u30e1\u30bd\u30c3\u30c9\u3092\u5b9f\u88c5\u3059\u308b\u969b\u306f\u3001\u4ee5\u4e0b\u306e\u70b9\u306b\u7279\u306b\u6ce8\u610f\u304c\u5fc5\u8981\u3067\u3059\u3002<\/p>\n<\/div>\n\n\n<ol class=\"wp-block-list is-style-sango-list-simple\"><div id=\"sgb-css-id-56\">\n<li><strong>null\u5b89\u5168\u6027<\/strong>\uff1a <code>Objects.equals()<\/code> \u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u3067\u3001null\u5024\u306e\u6bd4\u8f03\u3092\u5b89\u5168\u306b\u884c\u3048\u307e\u3059\u3002<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-57\">\n<li><strong>\u4e00\u8cab\u6027<\/strong>\uff1a \u53ef\u5909\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u5834\u5408\u3001equals() \u306e\u7d50\u679c\u304c\u6642\u9593\u3068\u3068\u3082\u306b\u5909\u5316\u3057\u306a\u3044\u3088\u3046\u6ce8\u610f\u304c\u5fc5\u8981\u3067\u3059\u3002<\/li>\n<\/div><\/ol>\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=\"\">\/\/ null\u5b89\u5168\u306a\u6bd4\u8f03\nreturn Objects.equals(this.name, other.name) &amp;&amp; this.age == other.age;<\/pre>\n\n\n<div id=\"sgb-css-id-58\">\n<h3 class=\"wp-block-heading\" id=\"i-13\">\u7d99\u627f\u6642\u306eequals()\u5b9f\u88c5\u306e\u843d\u3068\u3057\u7a74<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-59\">\n<p>\u7d99\u627f\u3092\u4f7f\u7528\u3059\u308b\u5834\u5408\u3001<code>equals()<\/code> \u30e1\u30bd\u30c3\u30c9\u306e\u5b9f\u88c5\u306b\u306f\u7279\u5225\u306a\u6ce8\u610f\u304c\u5fc5\u8981\u3067\u3059\u3002\u30b5\u30d6\u30af\u30e9\u30b9\u3067\u65b0\u3057\u3044\u30d5\u30a3\u30fc\u30eb\u30c9\u3092\u8ffd\u52a0\u3059\u308b\u5834\u5408\u3001\u30b9\u30fc\u30d1\u30fc\u30af\u30e9\u30b9\u306e <code>equals()<\/code> \u30e1\u30bd\u30c3\u30c9\u3092\u5358\u7d14\u306b\u62e1\u5f35\u3059\u308b\u3060\u3051\u3067\u306f\u3001\u5bfe\u79f0\u6027\u3084\u63a8\u79fb\u6027\u304c\u7834\u58ca\u3055\u308c\u308b\u53ef\u80fd\u6027\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-60\">\n<p>\u3053\u306e\u554f\u984c\u3092\u89e3\u6c7a\u3059\u308b\u306b\u306f\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u30a2\u30d7\u30ed\u30fc\u30c1\u304c\u8003\u3048\u3089\u308c\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<ol class=\"wp-block-list is-style-sango-list-simple\"><div id=\"sgb-css-id-61\">\n<li><strong>\u30b3\u30f3\u30dd\u30b8\u30b7\u30e7\u30f3\u512a\u5148<\/strong>\uff1a \u7d99\u627f\u306e\u4ee3\u308f\u308a\u306b\u30b3\u30f3\u30dd\u30b8\u30b7\u30e7\u30f3\u3092\u4f7f\u7528\u3059\u308b\u3002<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-62\">\n<li><strong>\u30bf\u30b0\u4ed8\u304d\u30af\u30e9\u30b9<\/strong>\uff1a \u30b9\u30fc\u30d1\u30fc\u30af\u30e9\u30b9\u306b\u578b\u30bf\u30b0\u3092\u5c0e\u5165\u3057\u3001\u30b5\u30d6\u30af\u30e9\u30b9\u3067\u305d\u308c\u3092\u4f7f\u7528\u3059\u308b\u3002<\/li>\n<\/div><\/ol>\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=\"\">public abstract class Shape {\n    private final ShapeType type;\n\n    \/\/ \u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u7b49\u306f\u7701\u7565\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        Shape shape = (Shape) obj;\n        return type == shape.type;\n    }\n\n    \/\/ hashCode() \u30e1\u30bd\u30c3\u30c9\u3082\u9069\u5207\u306b\u5b9f\u88c5\u3059\u308b\n}\n\npublic class Circle extends Shape {\n    private final double radius;\n\n    \/\/ \u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u7b49\u306f\u7701\u7565\n\n    @Override\n    public boolean equals(Object obj) {\n        if (!super.equals(obj)) return false;\n        Circle circle = (Circle) obj;\n        return Double.compare(circle.radius, radius) == 0;\n    }\n\n    \/\/ hashCode() \u30e1\u30bd\u30c3\u30c9\u3082\u9069\u5207\u306b\u5b9f\u88c5\u3059\u308b\n}<\/pre>\n\n\n<div id=\"sgb-css-id-63\">\n<h3 class=\"wp-block-heading\" id=\"i-14\">IDE\u6a5f\u80fd\u3068\u30e9\u30a4\u30d6\u30e9\u30ea\u306e\u6d3b\u7528<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-64\">\n<p>\u591a\u304f\u306eIDE\u306f <code>equals()<\/code> \u30e1\u30bd\u30c3\u30c9\u306e\u81ea\u52d5\u751f\u6210\u6a5f\u80fd\u3092\u63d0\u4f9b\u3057\u3066\u3044\u307e\u3059\u3002\u4f8b\u3048\u3070\u3001IntelliJ IDEA\u3067\u306f <code>Generate<\/code> \u30e1\u30cb\u30e5\u30fc\uff08Windows\/Linux: <code>Alt+Insert<\/code>, Mac: <code>Cmd+N<\/code>\uff09\u304b\u3089 <code>equals() and hashCode()<\/code> \u3092\u9078\u629e\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-65\">\n<p>\u307e\u305f\u3001Apache Commons Lang \u30e9\u30a4\u30d6\u30e9\u30ea\u306e <code>EqualsBuilder<\/code> \u30af\u30e9\u30b9\u3092\u4f7f\u7528\u3059\u308b\u3068\u3001\u3088\u308a\u7c21\u6f54\u306b <code>equals()<\/code> \u30e1\u30bd\u30c3\u30c9\u3092\u5b9f\u88c5\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=\"\">import org.apache.commons.lang3.builder.EqualsBuilder;\n\npublic class Person {\n    private final String name;\n    private final int age;\n\n    \/\/ \u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u7b49\u306f\u7701\u7565\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        Person person = (Person) obj;\n        return new EqualsBuilder()\n                .append(name, person.name)\n                .append(age, person.age)\n                .isEquals();\n    }\n\n    \/\/ hashCode() \u30e1\u30bd\u30c3\u30c9\u3082\u9069\u5207\u306b\u5b9f\u88c5\u3059\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\n}<\/pre>\n\n\n<div id=\"sgb-css-id-66\">\n<p>\u30ab\u30b9\u30bf\u30e0\u30af\u30e9\u30b9\u3067\u306e <code>equals()<\/code> \u30e1\u30bd\u30c3\u30c9\u306e\u6b63\u3057\u3044\u5b9f\u88c5\u306f\u3001Java \u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u306e\u91cd\u8981\u306a\u30b9\u30ad\u30eb\u306e\u4e00\u3064\u3067\u3059\u3002\u4e00\u822c\u5951\u7d04\u3092\u5b88\u308a\u3001null \u5b89\u5168\u6027\u3068\u4e00\u8cab\u6027\u3092\u78ba\u4fdd\u3059\u308b\u3053\u3068\u3067\u3001\u30d0\u30b0\u306e\u5c11\u306a\u3044\u5805\u7262\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<code>equals()<\/code> \u3068\u5bc6\u63a5\u306b\u95a2\u9023\u3059\u308b <code>hashCode()<\/code> \u30e1\u30bd\u30c3\u30c9\u306b\u3064\u3044\u3066\u8a73\u3057\u304f\u898b\u3066\u3044\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-67\">\n<h2 class=\"wp-block-heading\" id=\"i-15\">4. equals() \u3068 hashCode() \u306e\u6df1\u3044\u95a2\u4fc2<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-68\">\n<h3 class=\"wp-block-heading\" id=\"i-16\">\u306a\u305cequals()\u3092\u30aa\u30fc\u30d0\u30fc\u30e9\u30a4\u30c9\u3057\u305f\u3089hashCode()\u3082\u5fc5\u8981\u304b<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-69\">\n<p><code>equals()<\/code> \u30e1\u30bd\u30c3\u30c9\u3068 <code>hashCode()<\/code> \u30e1\u30bd\u30c3\u30c9\u306f\u3001Java \u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u30e2\u30c7\u30eb\u306b\u304a\u3044\u3066\u5bc6\u63a5\u306b\u95a2\u9023\u3057\u3066\u3044\u307e\u3059\u3002\u3053\u308c\u3089\u306e\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u7b49\u4fa1\u6027\u3068\u4e00\u610f\u6027\u3092\u5b9a\u7fa9\u3059\u308b\u4e0a\u3067\u91cd\u8981\u306a\u5f79\u5272\u3092\u679c\u305f\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-70\">\n<p>Java\u8a00\u8a9e\u4ed5\u69d8\u3067\u306f\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306a <code>equals()<\/code> \u3068 <code>hashCode()<\/code> \u306e\u95a2\u4fc2\u3092\u5b9a\u3081\u3066\u3044\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-74\">\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\"><code>equals()<\/code> \u3068 <code>hashCode()<\/code> \u306e\u95a2\u4fc2<\/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-71\">\n<li>2\u3064\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u304c <code>equals()<\/code> \u3067\u7b49\u3057\u3044\u3068\u5224\u65ad\u3055\u308c\u305f\u5834\u5408\u3001\u305d\u308c\u3089\u306e <code>hashCode()<\/code> \u5024\u306f\u540c\u3058\u3067\u306a\u3051\u308c\u3070\u306a\u3089\u306a\u3044\u3002<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-72\">\n<li>2\u3064\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e <code>hashCode()<\/code> \u5024\u304c\u7570\u306a\u308b\u5834\u5408\u3001\u305d\u308c\u3089\u306f <code>equals()<\/code> \u3067\u7b49\u3057\u304f\u306a\u3044\u3068\u5224\u65ad\u3055\u308c\u306a\u3051\u308c\u3070\u306a\u3089\u306a\u3044\u3002<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-73\">\n<li>\u305f\u3060\u3057\u30012\u3064\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e <code>hashCode()<\/code> \u5024\u304c\u540c\u3058\u3067\u3042\u3063\u3066\u3082\u3001\u305d\u308c\u3089\u304c <code>equals()<\/code> \u3067\u7b49\u3057\u3044\u3068\u306f\u9650\u3089\u306a\u3044\u3002<\/li>\n<\/div><\/ol>\n<\/div><\/div>\n<\/div>\n\n<div id=\"sgb-css-id-75\">\n<p>\u3053\u308c\u3089\u306e\u898f\u5247\u3092\u5b88\u3089\u306a\u3044\u3068\u3001<code>HashMap<\/code>\u3001<code>HashSet<\/code> \u306a\u3069\u306e\u30cf\u30c3\u30b7\u30e5\u30d9\u30fc\u30b9\u306e\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u3067\u4e88\u671f\u305b\u306c\u52d5\u4f5c\u304c\u767a\u751f\u3059\u308b\u53ef\u80fd\u6027\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-76\">\n<p>\u4ee5\u4e0b\u306b\u3001<code>equals()<\/code> \u3068 <code>hashCode()<\/code> \u306e\u4e00\u8cab\u6027\u304c\u7834\u3089\u308c\u305f\u5834\u5408\u306e\u554f\u984c\u4f8b\u3092\u793a\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=\"\">public class InconsistentPerson {\n    private String name;\n    private int age;\n\n    \/\/ \u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u3001\u30b2\u30c3\u30bf\u30fc\u3001\u30bb\u30c3\u30bf\u30fc\u306f\u7701\u7565\n\n    @Override\n    public boolean equals(Object o) {\n        if (this == o) return true;\n        if (!(o instanceof InconsistentPerson)) return false;\n        InconsistentPerson that = (InconsistentPerson) o;\n        return age == that.age &amp;&amp; Objects.equals(name, that.name);\n    }\n\n    \/\/ hashCode()\u3092\u30aa\u30fc\u30d0\u30fc\u30e9\u30a4\u30c9\u3057\u3066\u3044\u306a\u3044\uff01\n\n    public static void main(String[] args) {\n        Map&lt;InconsistentPerson, String&gt; map = new HashMap&lt;&gt;();\n        InconsistentPerson person1 = new InconsistentPerson(\"Alice\", 30);\n        InconsistentPerson person2 = new InconsistentPerson(\"Alice\", 30);\n\n        map.put(person1, \"\u30c7\u30fc\u30bf1\");\n        System.out.println(map.get(person2)); \/\/ null \u304c\u51fa\u529b\u3055\u308c\u308b\uff01\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-77\">\n<p>\u3053\u306e\u4f8b\u3067\u306f\u3001<code>person1<\/code> \u3068 <code>person2<\/code> \u306f <code>equals()<\/code> \u3067\u7b49\u3057\u3044\u306b\u3082\u304b\u304b\u308f\u3089\u305a\u3001<code>hashCode()<\/code> \u304c\u9069\u5207\u306b\u30aa\u30fc\u30d0\u30fc\u30e9\u30a4\u30c9\u3055\u308c\u3066\u3044\u306a\u3044\u305f\u3081\u3001<code>HashMap<\/code> \u5185\u3067\u5225\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3068\u3057\u3066\u6271\u308f\u308c\u3066\u3057\u307e\u3044\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-78\">\n<h3 class=\"wp-block-heading\" id=\"i-17\">\u52b9\u7387\u7684\u306ahashCode()\u306e\u5b9f\u88c5\u30c6\u30af\u30cb\u30c3\u30af<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-79\">\n<p>\u52b9\u7387\u7684\u3067\u9069\u5207\u306a <code>hashCode()<\/code> \u3092\u5b9f\u88c5\u3059\u308b\u306b\u306f\u3001\u4ee5\u4e0b\u306e\u30c6\u30af\u30cb\u30c3\u30af\u304c\u6709\u52b9\u3067\u3059\u3002<\/p>\n<\/div>\n\n\n<ol class=\"wp-block-list is-style-sango-list-simple\"><div id=\"sgb-css-id-80\">\n<li><strong>\u7d20\u6570\u306e\u4f7f\u7528<\/strong>\uff1a \u8a08\u7b97\u306e\u57fa\u6570\u3068\u3057\u3066\u7d20\u6570\uff08\u4f8b\uff1a31\uff09\u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u30cf\u30c3\u30b7\u30e5\u306e\u5206\u5e03\u3092\u6539\u5584\u3057\u307e\u3059\u3002<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-81\">\n<li><strong>\u30d3\u30c3\u30c8\u64cd\u4f5c<\/strong>\uff1a \u30b7\u30d5\u30c8\u6f14\u7b97\u3092\u4f7f\u7528\u3057\u3066\u3001\u8a08\u7b97\u3092\u9ad8\u901f\u5316\u3057\u307e\u3059\u3002<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-82\">\n<li><strong>Objects.hash()\u306e\u5229\u7528<\/strong>\uff1a Java 7\u4ee5\u964d\u3067\u306f\u3001<code>Objects.hash()<\/code> \u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u7528\u3057\u3066\u7c21\u5358\u306b <code>hashCode()<\/code> \u3092\u5b9f\u88c5\u3067\u304d\u307e\u3059\u3002<\/li>\n<\/div><\/ol>\n\n\n<div id=\"sgb-css-id-83\">\n<p>\u4ee5\u4e0b\u306b\u3001\u3053\u308c\u3089\u306e\u30c6\u30af\u30cb\u30c3\u30af\u3092\u7528\u3044\u305f <code>hashCode()<\/code> \u306e\u5b9f\u88c5\u4f8b\u3092\u793a\u3057\u307e\u3059\u3002<br><\/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 Person {\n    private String name;\n    private int;\n    \/\/ \u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u3001\u30b2\u30c3\u30bf\u30fc\u3001\u30bb\u30c3\u30bf\u30fc\u306f\u7701\u7565\n\n    @Override\n    public boolean equals(Object o) {\n        if (this == o) return true;\n        if (!(o instanceof Person)) return false;\n        Person person = (Person) o;\n        return age == person.age &amp;&amp; Objects.equals(name, person.name);\n    }\n    \n    @Override\n    public int hashCode() {\n        int result = 17; \/\/ \u7d20\u6570\u3092\u521d\u671f\u5024\u3068\u3057\u3066\u4f7f\u7528\n        result = 31 * result + age; \/\/ 31\u3092\u4e57\u7b97\uff08\u30d3\u30c3\u30c8\u6f14\u7b97\u3067\u6700\u9069\u5316\u53ef\u80fd: (result &lt;&lt; 5) - result\uff09\n        result = 31 * result + (name != null ? name.hashCode() : 0);\n        return result;\n    }\n    \n    \/\/ \u307e\u305f\u306f\u3001Java 7\u4ee5\u964d\u3067\u306f\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u7c21\u6f54\u306b\u66f8\u3051\u307e\u3059\n    \/\/ @Override\n    \/\/ public int hashCode() {\n    \/\/     return Objects.hash(name, age);\n    \/\/ }\n\n}<\/pre>\n\n\n<div id=\"sgb-css-id-84\">\n<h3 class=\"wp-block-heading\" id=\"i-18\">hashCode()\u5b9f\u88c5\u6642\u306e\u6ce8\u610f\u70b9<\/h3>\n<\/div>\n\n\n<ol class=\"wp-block-list is-style-sango-list-simple\"><div id=\"sgb-css-id-85\">\n<li><strong>\u4e00\u8cab\u6027<\/strong>\uff1a \u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u72b6\u614b\u304c\u5909\u308f\u3089\u306a\u3044\u9650\u308a\u3001\u540c\u3058 <code>hashCode()<\/code> \u5024\u3092\u8fd4\u3059\u5fc5\u8981\u304c\u3042\u308b\u3002<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-86\">\n<li><strong>\u5206\u6563\u6027<\/strong>\uff1a \u7570\u306a\u308b\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306b\u5bfe\u3057\u3066\u3001\u3067\u304d\u308b\u3060\u3051\u7570\u306a\u308b\u30cf\u30c3\u30b7\u30e5\u5024\u3092\u751f\u6210\u3059\u308b\u3088\u3046\u306b\u3059\u308b\u3002<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-87\">\n<li><strong>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9<\/strong>\uff1a <code>hashCode()<\/code> \u306e\u8a08\u7b97\u306f\u9ad8\u901f\u3067\u3042\u308b\u5fc5\u8981\u304c\u3042\u308b\u3002<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-88\">\n<li><strong>\u4e0d\u5909\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u6d3b\u7528<\/strong>\uff1a \u53ef\u80fd\u306a\u9650\u308a\u4e0d\u5909\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u4f7f\u7528\u3057\u3001<code>hashCode()<\/code> \u306e\u7d50\u679c\u3092\u30ad\u30e3\u30c3\u30b7\u30e5\u3059\u308b\u3053\u3068\u3067\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u5411\u4e0a\u3055\u305b\u3089\u308c\u307e\u3059\u3002<\/li>\n<\/div><\/ol>\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=\"\">public final class ImmutablePerson {\n    private final String name;\n    private final int age;\n    private final int cachedHashCode; \/\/ \u30cf\u30c3\u30b7\u30e5\u30b3\u30fc\u30c9\u3092\u30ad\u30e3\u30c3\u30b7\u30e5\n\n    public ImmutablePerson(String name, int age) {\n        this.name = name;\n        this.age = age;\n        this.cachedHashCode = computeHashCode();\n    }\n\n    private int computeHashCode() {\n        return Objects.hash(name, age);\n    }\n\n    @Override\n    public int hashCode() {\n        return cachedHashCode;\n    }\n\n    \/\/ equals()\u30e1\u30bd\u30c3\u30c9\u306f\u7701\u7565\n}<\/pre>\n\n\n<div id=\"sgb-css-id-89\">\n<h3 class=\"wp-block-heading\" id=\"i-19\">\u307e\u3068\u3081<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-90\">\n<p><code>equals()<\/code> \u3068 <code>hashCode()<\/code> \u306f\u5bc6\u63a5\u306b\u95a2\u9023\u3057\u3066\u304a\u308a\u3001\u4e21\u65b9\u3092\u9069\u5207\u306b\u5b9f\u88c5\u3059\u308b\u3053\u3068\u304c\u91cd\u8981\u3067\u3059\u3002\u3053\u308c\u306b\u3088\u308a\u3001\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u7b49\u4fa1\u6027\u304c\u6b63\u3057\u304f\u5224\u65ad\u3055\u308c\u3001\u30cf\u30c3\u30b7\u30e5\u30d9\u30fc\u30b9\u306e\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u3067\u671f\u5f85\u901a\u308a\u306b\u52d5\u4f5c\u3057\u307e\u3059\u3002\u52b9\u7387\u7684\u306a <code>hashCode()<\/code> \u306e\u5b9f\u88c5\u306f\u3001\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u306b\u3082\u76f4\u63a5\u5f71\u97ff\u3092\u4e0e\u3048\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-91\">\n<p>\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001Java 7\u4ee5\u964d\u3067\u5c0e\u5165\u3055\u308c\u305f <code>equals()<\/code> \u3068 <code>hashCode()<\/code> \u306e\u5b9f\u88c5\u306b\u95a2\u3059\u308b\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\u306b\u3064\u3044\u3066\u8a73\u3057\u304f\u898b\u3066\u3044\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-92\">\n<h2 class=\"wp-block-heading\" id=\"i-20\">5. Java 7\u4ee5\u964d\u306e equals() \u5b9f\u88c5\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-93\">\n<p>Java 7\u4ee5\u964d\u3001<code>equals()<\/code> \u3068 <code>hashCode()<\/code> \u30e1\u30bd\u30c3\u30c9\u306e\u5b9f\u88c5\u306b\u95a2\u3059\u308b\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\u304c\u5927\u304d\u304f\u9032\u5316\u3057\u307e\u3057\u305f\u3002\u65b0\u3057\u3044\u6a5f\u80fd\u3084\u30e9\u30a4\u30d6\u30e9\u30ea\u3092\u6d3b\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u3088\u308a\u7c21\u6f54\u3067\u5805\u7262\u306a\u30b3\u30fc\u30c9\u3092\u66f8\u304f\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-94\">\n<h3 class=\"wp-block-heading\" id=\"i-21\">Objects.equals()\u306e\u6d3b\u7528\uff1anull\u5b89\u5168\u6027\u306e\u5411\u4e0a<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-95\">\n<p>Java 7\u3067\u5c0e\u5165\u3055\u308c\u305f <code>Objects<\/code> \u30af\u30e9\u30b9\u306f\u3001<code>null<\/code> \u306e\u5b89\u5168\u306a\u6bd4\u8f03\u3092\u7c21\u5358\u306b\u884c\u3048\u308b\u3088\u3046\u306b\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=\"\">public boolean equals(Object o) {\n    if (this == o) return true;\n    if (!(o instanceof Person)) return false;\n    Person person = (Person) o;\n    return age == person.age &amp;&amp; \n           Objects.equals(name, person.name); \/\/ null\u5b89\u5168\u306a\u6bd4\u8f03\n}<\/pre>\n\n\n<div id=\"sgb-css-id-96\">\n<p><code>Objects.equals()<\/code> \u306f\u5185\u90e8\u3067 <code>null<\/code> \u30c1\u30a7\u30c3\u30af\u3092\u884c\u3046\u305f\u3081\u3001\u660e\u793a\u7684\u306a <code>null<\/code> \u30c1\u30a7\u30c3\u30af\u304c\u4e0d\u8981\u306b\u306a\u308a\u3001\u30b3\u30fc\u30c9\u304c\u3088\u308a\u30af\u30ea\u30fc\u30f3\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-97\">\n<h3 class=\"wp-block-heading\" id=\"i-22\">\u52b9\u7387\u7684\u306ahashCode()\u5b9f\u88c5\uff1aObjects.hash()<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-98\">\n<p>\u540c\u69d8\u306b\u3001<code>Objects.hash()<\/code> \u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u7c21\u6f54\u3067\u52b9\u7387\u7684\u306a <code>hashCode()<\/code> \u30e1\u30bd\u30c3\u30c9\u3092\u5b9f\u88c5\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=\"\">@Override\npublic int hashCode() {\n    return Objects.hash(name, age);\n}<\/pre>\n\n\n<div id=\"sgb-css-id-99\">\n<p>\u3053\u306e\u30e1\u30bd\u30c3\u30c9\u306f\u5185\u90e8\u3067\u6700\u9069\u5316\u3055\u308c\u3066\u304a\u308a\u3001\u9069\u5207\u306a\u30cf\u30c3\u30b7\u30e5\u5024\u306e\u5206\u6563\u3092\u4fdd\u8a3c\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-100\">\n<h3 class=\"wp-block-heading\" id=\"i-23\">Java 7\u306eDiamond Operator (&lt;&gt;)<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-101\">\n<p>\u578b\u63a8\u8ad6\u3092\u6d3b\u7528\u3059\u308bDiamond Operator\u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u30b3\u30fc\u30c9\u306e\u53ef\u8aad\u6027\u304c\u5411\u4e0a\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=\"\">Map&lt;Person, String&gt; personMap = new HashMap&lt;&gt;(); \/\/ \u578b\u306e\u660e\u793a\u7684\u306a\u6307\u5b9a\u304c\u4e0d\u8981<\/pre>\n\n\n<div id=\"sgb-css-id-102\">\n<h3 class=\"wp-block-heading\" id=\"i-24\">Apache Commons Lang\uff1aEqualsBuilder for \u7c21\u6f54\u306aequals()<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-103\">\n<p>Apache Commons Lang\u30e9\u30a4\u30d6\u30e9\u30ea\u306e <code>EqualsBuilder<\/code> \u3092\u4f7f\u7528\u3059\u308b\u3068\u3001\u3088\u308a\u5ba3\u8a00\u7684\u306a\u65b9\u6cd5\u3067 <code>equals()<\/code> \u30e1\u30bd\u30c3\u30c9\u3092\u5b9f\u88c5\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=\"\">@Override\npublic boolean equals(Object o) {\n    if (this == o) return true;\n    if (!(o instanceof Person)) return false;\n    Person person = (Person) o;\n    return new EqualsBuilder()\n               .append(age, person.age)\n               .append(name, person.name)\n               .isEquals();\n}<\/pre>\n\n\n<div id=\"sgb-css-id-104\">\n<p>\u540c\u69d8\u306b\u3001<code>HashCodeBuilder<\/code> \u3092\u4f7f\u7528\u3057\u3066 <code>hashCode()<\/code> \u30e1\u30bd\u30c3\u30c9\u3092\u5b9f\u88c5\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=\"\">@Override\npublic int hashCode() {\n    return new HashCodeBuilder(17, 37)\n               .append(name)\n               .append(age)\n               .toHashCode();\n}<\/pre>\n\n\n<div id=\"sgb-css-id-105\">\n<h3 class=\"wp-block-heading\" id=\"i-25\">Java 8\u4ee5\u964d\uff1aOptional \u30af\u30e9\u30b9\u306e\u6d3b\u7528<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-106\">\n<p>Java 8\u3067\u5c0e\u5165\u3055\u308c\u305f <code>Optional<\/code> \u30af\u30e9\u30b9\u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u3067\u3001<code>null<\/code> \u5024\u306e\u51e6\u7406\u3092\u3088\u308a\u660e\u793a\u7684\u304b\u3064\u5b89\u5168\u306b\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=\"\">public boolean equals(Object o) {\n    if (this == o) return true;\n    if (!(o instanceof Person)) return false;\n    Person person = (Person) o;\n    return age == person.age &amp;&amp; \n           Optional.ofNullable(name).equals(Optional.ofNullable(person.name));\n}<\/pre>\n\n\n<div id=\"sgb-css-id-107\">\n<h3 class=\"wp-block-heading\" id=\"i-26\">Java 9\u4ee5\u964d\uff1a\u4e0d\u5909\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u30d5\u30a1\u30af\u30c8\u30ea\u30e1\u30bd\u30c3\u30c9<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-108\">\n<p>Java 9\u4ee5\u964d\u3067\u306f\u3001\u4e0d\u5909\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u3092\u7c21\u5358\u306b\u4f5c\u6210\u3067\u304d\u308b\u30d5\u30a1\u30af\u30c8\u30ea\u30e1\u30bd\u30c3\u30c9\u304c\u5c0e\u5165\u3055\u308c\u307e\u3057\u305f\u3002\u3053\u308c\u3089\u306f <code>equals()<\/code> \u3068 <code>hashCode()<\/code> \u306e\u5b9f\u88c5\u306b\u304a\u3044\u3066\u3001\u4e0d\u5909\u6027\u3092\u4fdd\u8a3c\u3059\u308b\u306e\u306b\u5f79\u7acb\u3061\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 class ImmutablePerson {\n    private final String name;\n    private final int age;\n    private final List&lt;String&gt; nicknames;\n\n    public ImmutablePerson(String name, int age, List&lt;String&gt; nicknames) {\n        this.name = name;\n        this.age = age;\n        this.nicknames = List.copyOf(nicknames); \/\/ Java 10\u4ee5\u964d\n    }\n\n    \/\/ equals() \u3068 hashCode() \u306e\u5b9f\u88c5...\n}<\/pre>\n\n\n<div id=\"sgb-css-id-109\">\n<h3 class=\"wp-block-heading\" id=\"i-27\">IDE\u306e\u30b5\u30dd\u30fc\u30c8\u6d3b\u7528<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-110\">\n<p>\u6700\u65b0\u306eIDE\uff08IntelliJ IDEA, Eclipse\uff09\u306f\u3001<code>equals()<\/code> \u3068 <code>hashCode()<\/code> \u30e1\u30bd\u30c3\u30c9\u306e\u81ea\u52d5\u751f\u6210\u6a5f\u80fd\u304c\u5927\u5e45\u306b\u6539\u5584\u3055\u308c\u3066\u3044\u307e\u3059\u3002\u3053\u308c\u3089\u306e\u6a5f\u80fd\u3092\u6d3b\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u30a8\u30e9\u30fc\u3092\u6e1b\u3089\u3057\u3001\u6700\u65b0\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\u306b\u6cbf\u3063\u305f\u5b9f\u88c5\u3092\u7c21\u5358\u306b\u884c\u3048\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-111\">\n<h3 class=\"wp-block-heading\" id=\"i-28\">\u307e\u3068\u3081<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-112\">\n<p>Java 7\u4ee5\u964d\u306e\u65b0\u6a5f\u80fd\u3084\u30e9\u30a4\u30d6\u30e9\u30ea\u3092\u6d3b\u7528\u3059\u308b\u3053\u3068\u3067\u3001<code>equals()<\/code> \u3068 <code>hashCode()<\/code> \u30e1\u30bd\u30c3\u30c9\u306e\u5b9f\u88c5\u304c\u3088\u308a\u7c21\u6f54\u3067\u5805\u7262\u306b\u306a\u308a\u307e\u3057\u305f\u3002<code>Objects<\/code> \u30af\u30e9\u30b9\u306e\u4f7f\u7528\u3001Apache Commons Lang\u3084Google Guava\u306a\u3069\u306e\u5916\u90e8\u30e9\u30a4\u30d6\u30e9\u30ea\u306e\u6d3b\u7528\u3001\u305d\u3057\u3066\u6700\u65b0\u306eJava\u6a5f\u80fd\u306e\u63a1\u7528\u306b\u3088\u308a\u3001\u958b\u767a\u8005\u306f\u3088\u308a\u4fe1\u983c\u6027\u306e\u9ad8\u3044\u30b3\u30fc\u30c9\u3092\u52b9\u7387\u7684\u306b\u66f8\u304f\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-113\">\n<p>\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u3053\u308c\u3089\u306e\u5b9f\u88c5\u65b9\u6cd5\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3068\u6700\u9069\u5316\u30c6\u30af\u30cb\u30c3\u30af\u306b\u3064\u3044\u3066\u8a73\u3057\u304f\u898b\u3066\u3044\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-114\">\n<h2 class=\"wp-block-heading\" id=\"i-29\">6. equals()\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3068\u6700\u9069\u5316\u30c6\u30af\u30cb\u30c3\u30af<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-115\">\n<p><code>equals()<\/code> \u30e1\u30bd\u30c3\u30c9\u306f\u3001\u7279\u306b\u5927\u898f\u6a21\u306a\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3084\u30c7\u30fc\u30bf\u96c6\u7d04\u578b\u306e\u30b7\u30b9\u30c6\u30e0\u3067\u306f\u983b\u7e41\u306b\u547c\u3073\u51fa\u3055\u308c\u308b\u305f\u3081\u3001\u305d\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u306f\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u5168\u4f53\u306e\u6027\u80fd\u306b\u5927\u304d\u306a\u5f71\u97ff\u3092\u4e0e\u3048\u308b\u53ef\u80fd\u6027\u304c\u3042\u308a\u307e\u3059\u3002\u672c\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001<code>equals()<\/code> \u30e1\u30bd\u30c3\u30c9\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u6700\u9069\u5316\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-116\">\n<h3 class=\"wp-block-heading\" id=\"i-30\">\u65e9\u671f\u30ea\u30bf\u30fc\u30f3\u3067\u52b9\u7387\u30a2\u30c3\u30d7\uff1aequals()\u306e\u6700\u9069\u5316\u6226\u7565<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-117\">\n<p>\u65e9\u671f\u30ea\u30bf\u30fc\u30f3\u306f\u3001<code>equals()<\/code> \u30e1\u30bd\u30c3\u30c9\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u5411\u4e0a\u3055\u305b\u308b\u6700\u3082\u52b9\u679c\u7684\u306a\u65b9\u6cd5\u306e\u4e00\u3064\u3067\u3059\u3002\u6761\u4ef6\u3092\u30c1\u30a7\u30c3\u30af\u3057\u3001\u3067\u304d\u308b\u3060\u3051\u65e9\u304f\u7d50\u679c\u3092\u8fd4\u3059\u3053\u3068\u3067\u3001\u4e0d\u8981\u306a\u51e6\u7406\u3092\u907f\u3051\u308b\u3053\u3068\u304c\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=\"\">@Override\npublic boolean equals(Object o) {\n    if (this == o) return true;  \/\/ \u540c\u4e00\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u5834\u5408\u3001\u5373\u5ea7\u306btrue\u3092\u8fd4\u3059\n    if (o == null || getClass() != o.getClass()) return false;  \/\/ null\u30c1\u30a7\u30c3\u30af\u3068\u30af\u30e9\u30b9\u30c1\u30a7\u30c3\u30af\n\n    Person person = (Person) o;\n\n    if (age != person.age) return false;  \/\/ \u57fa\u672c\u578b\u306e\u6bd4\u8f03\u3092\u5148\u306b\u884c\u3046\n    return Objects.equals(name, person.name);  \/\/ \u6700\u5f8c\u306b\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u6bd4\u8f03\n}<\/pre>\n\n\n<div id=\"sgb-css-id-118\">\n<p>\u3053\u306e\u30a2\u30d7\u30ed\u30fc\u30c1\u306b\u3088\u308a\u3001\u591a\u304f\u306e\u30b1\u30fc\u30b9\u3067\u6bd4\u8f03\u51e6\u7406\u3092\u65e9\u671f\u306b\u7d42\u4e86\u3055\u305b\u308b\u3053\u3068\u304c\u3067\u304d\u3001\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u304c\u5411\u4e0a\u3057\u307e\u3059\u3002JMH\u3092\u4f7f\u7528\u3057\u305f\u30d9\u30f3\u30c1\u30de\u30fc\u30af\u3067\u306f\u3001\u65e9\u671f\u30ea\u30bf\u30fc\u30f3\u3092\u5b9f\u88c5\u3059\u308b\u3053\u3068\u3067\u3001\u5e73\u5747\u3057\u3066\u7d0415-20%\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u5411\u4e0a\u304c\u898b\u3089\u308c\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-119\">\n<h3 class=\"wp-block-heading\" id=\"i-31\">\u30d5\u30a3\u30fc\u30eb\u30c9\u6bd4\u8f03\u306e\u9806\u5e8f\u6700\u9069\u5316<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-120\">\n<p>\u30d5\u30a3\u30fc\u30eb\u30c9\u306e\u6bd4\u8f03\u9806\u5e8f\u3082\u91cd\u8981\u3067\u3059\u3002\u4ee5\u4e0b\u306e\u9806\u5e8f\u3067\u6bd4\u8f03\u3092\u884c\u3046\u3053\u3068\u3067\u3001\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u6700\u9069\u5316\u3067\u304d\u307e\u3059\u3002<\/p>\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\">\u30d5\u30a3\u30fc\u30eb\u30c9\u6bd4\u8f03\u306e\u9806\u5e8f<\/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>\u6bd4\u8f03\u30b3\u30b9\u30c8\u304c\u4f4e\u3044\u30d5\u30a3\u30fc\u30eb\u30c9\uff08\u57fa\u672c\u578b\uff09<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-122\">\n<li>\u4e0d\u4e00\u81f4\u306e\u53ef\u80fd\u6027\u304c\u9ad8\u3044\u30d5\u30a3\u30fc\u30eb\u30c9<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-123\">\n<li>\u6bd4\u8f03\u30b3\u30b9\u30c8\u304c\u9ad8\u3044\u30d5\u30a3\u30fc\u30eb\u30c9\uff08\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u578b\u3001\u7279\u306b\u914d\u5217\u3084\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\uff09<\/li>\n<\/div><\/ol>\n<\/div><\/div>\n<\/div>\n\n<div id=\"sgb-css-id-125\">\n<p>\u3053\u306e\u9806\u5e8f\u306b\u5f93\u3046\u3053\u3068\u3067\u3001\u591a\u304f\u306e\u30b1\u30fc\u30b9\u3067\u65e9\u671f\u306b\u4e0d\u4e00\u81f4\u3092\u691c\u51fa\u3057\u3001\u4e0d\u8981\u306a\u6bd4\u8f03\u3092\u907f\u3051\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-126\">\n<h3 class=\"wp-block-heading\" id=\"i-32\">hashCode()\u306e\u30ad\u30e3\u30c3\u30b7\u30e5\u6d3b\u7528<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-127\">\n<p><code>hashCode()<\/code> \u306e\u7d50\u679c\u3092\u30ad\u30e3\u30c3\u30b7\u30e5\u3059\u308b\u3053\u3068\u3067\u3001\u7279\u306b\u4e0d\u5909\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u5834\u5408\u3001\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u5927\u5e45\u306b\u5411\u4e0a\u3055\u305b\u308b\u3053\u3068\u304c\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 final class ImmutablePerson {\n    private final String name;\n    private final int age;\n    private final int cachedHashCode;\n\n    public ImmutablePerson(String name, int age) {\n        this.name = name;\n        this.age = age;\n        this.cachedHashCode = computeHashCode();\n    }\n\n    private int computeHashCode() {\n        return Objects.hash(name, age);\n    }\n\n    @Override\n    public int hashCode() {\n        return cachedHashCode;\n    }\n\n    \/\/ equals()\u30e1\u30bd\u30c3\u30c9\u306f\u7701\u7565\n}<\/pre>\n\n\n<div id=\"sgb-css-id-128\">\n<p>\u3053\u306e\u30a2\u30d7\u30ed\u30fc\u30c1\u306f\u3001\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u751f\u6210\u6642\u306b\u5c11\u3057\u591a\u304f\u306e\u30e1\u30e2\u30ea\u3092\u4f7f\u7528\u3057\u307e\u3059\u304c\u3001<code>hashCode()<\/code> \u306e\u547c\u3073\u51fa\u3057\u304c\u983b\u7e41\u306a\u5834\u5408\u3001\u5168\u4f53\u7684\u306a\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u304c\u5411\u4e0a\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-129\">\n<h3 class=\"wp-block-heading\" id=\"i-33\">\u5927\u898f\u6a21\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3067\u306eequals()\u3068\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u8003\u5bdf<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-130\">\n<p>\u5927\u898f\u6a21\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3067\u306f\u3001<code>equals()<\/code> \u306e\u547c\u3073\u51fa\u3057\u304c\u4e88\u60f3\u4ee5\u4e0a\u306b\u591a\u304f\u306a\u308b\u3053\u3068\u304c\u3042\u308a\u307e\u3059\u3002\u7279\u306b\u3001HashMap\u3084HashSet\u306a\u3069\u306e\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u3092\u983b\u7e41\u306b\u4f7f\u7528\u3059\u308b\u5834\u5408\u3001<code>equals()<\/code> \u3068 <code>hashCode()<\/code> \u306e\u5b9f\u88c5\u304c\u5168\u4f53\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u306b\u5927\u304d\u304f\u5f71\u97ff\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-131\">\n<p>\u30d7\u30ed\u30d5\u30a1\u30a4\u30ea\u30f3\u30b0\u30c4\u30fc\u30eb\u3092\u4f7f\u7528\u3057\u3066\u3001<code>equals()<\/code> \u30e1\u30bd\u30c3\u30c9\u306e\u547c\u3073\u51fa\u3057\u983b\u5ea6\u3068\u5b9f\u884c\u6642\u9593\u3092\u6e2c\u5b9a\u3059\u308b\u3053\u3068\u3092\u304a\u52e7\u3081\u3057\u307e\u3059\u3002Java Flight Recorder (JFR) \u3084YourKit \u306a\u3069\u306e\u30c4\u30fc\u30eb\u3092\u4f7f\u7528\u3059\u308b\u3068\u3001\u8a73\u7d30\u306a\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u5206\u6790\u304c\u53ef\u80fd\u3067\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-132\">\n<h3 class=\"wp-block-heading\" id=\"i-34\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3068\u53ef\u8aad\u6027\u306e\u30d0\u30e9\u30f3\u30b9<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-133\">\n<p>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u306e\u6700\u9069\u5316\u306f\u91cd\u8981\u3067\u3059\u304c\u3001\u30b3\u30fc\u30c9\u306e\u53ef\u8aad\u6027\u3068\u4fdd\u5b88\u6027\u3092\u72a0\u7272\u306b\u3057\u3066\u306f\u3044\u3051\u307e\u305b\u3093\u3002\u904e\u5ea6\u306b\u8907\u96d1\u306a\u6700\u9069\u5316\u306f\u907f\u3051\u3001\u30c1\u30fc\u30e0\u306e\u30b3\u30fc\u30c7\u30a3\u30f3\u30b0\u898f\u7d04\u306b\u5f93\u3044\u3064\u3064\u3001\u9069\u5ea6\u306a\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6539\u5584\u3092\u76ee\u6307\u3059\u3079\u304d\u3067\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-134\">\n<p>\u6700\u9069\u5316\u306e\u524d\u5f8c\u3067\u30d9\u30f3\u30c1\u30de\u30fc\u30af\u3092\u53d6\u308a\u3001\u5b9f\u969b\u306e\u6539\u5584\u52b9\u679c\u3092\u78ba\u8a8d\u3059\u308b\u3053\u3068\u304c\u91cd\u8981\u3067\u3059\u3002JMH (Java Microbenchmark Harness) \u3092\u4f7f\u7528\u3059\u308b\u3068\u3001\u6b63\u78ba\u306a\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6e2c\u5b9a\u304c\u53ef\u80fd\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=\"\">@Benchmark\npublic void testEquals(Blackhole blackhole) {\n    Person p1 = new Person(\"Alice\", 30);\n    Person p2 = new Person(\"Alice\", 30);\n    blackhole.consume(p1.equals(p2));\n}<\/pre>\n\n\n<div id=\"sgb-css-id-135\">\n<p>\u3053\u306e\u3088\u3046\u306a\u30d9\u30f3\u30c1\u30de\u30fc\u30af\u3092\u4f7f\u7528\u3057\u3066\u3001\u6700\u9069\u5316\u306e\u52b9\u679c\u3092\u5b9a\u91cf\u7684\u306b\u8a55\u4fa1\u3057\u3001\u6295\u8cc7\u5bfe\u52b9\u679c\u306e\u9ad8\u3044\u6700\u9069\u5316\u306b\u6ce8\u529b\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-136\">\n<p>\u9069\u5207\u306b\u6700\u9069\u5316\u3055\u308c\u305f <code>equals()<\/code> \u30e1\u30bd\u30c3\u30c9\u306f\u3001\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u306e\u5168\u4f53\u7684\u306a\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u5411\u4e0a\u3055\u305b\u308b\u91cd\u8981\u306a\u8981\u7d20\u3068\u306a\u308a\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001<code>equals()<\/code> \u306e\u5b9f\u88c5\u306b\u304a\u3051\u308b common \u306a\u30df\u30b9\u3068\u305d\u306e\u56de\u907f\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-137\">\n<h2 class=\"wp-block-heading\" id=\"i-35\">7. \u3088\u304f\u3042\u308b equals() \u306e\u5b9f\u88c5\u30df\u30b9\u3068\u305d\u306e\u56de\u907f\u65b9\u6cd5<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-138\">\n<p>equals() \u30e1\u30bd\u30c3\u30c9\u306e\u6b63\u3057\u3044\u5b9f\u88c5\u306f\u3001Java \u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u306b\u304a\u3044\u3066\u91cd\u8981\u3067\u3059\u304c\u3001\u540c\u6642\u306b\u8aa4\u308a\u3082\u767a\u751f\u3057\u3084\u3059\u3044\u9818\u57df\u3067\u3059\u3002\u3053\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u3088\u304f\u3042\u308b\u5b9f\u88c5\u30df\u30b9\u3068\u305d\u306e\u56de\u907f\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-139\">\n<h3 class=\"wp-block-heading\" id=\"i-36\">\u5bfe\u79f0\u6027\u9055\u53cd\u3092\u907f\u3051\u308b\uff1a\u53cc\u65b9\u5411\u306e\u7b49\u4fa1\u6027\u3092\u78ba\u4fdd<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-140\">\n<p>\u5bfe\u79f0\u6027\u306f\u3001x.equals(y) \u304c true \u306e\u5834\u5408\u3001y.equals(x) \u3082 true \u3067\u306a\u3051\u308c\u3070\u306a\u3089\u306a\u3044\u3068\u3044\u3046\u6027\u8cea\u3067\u3059\u3002\u3053\u306e\u9055\u53cd\u306f\u7279\u306b\u3001\u7570\u306a\u308b\u30af\u30e9\u30b9\u9593\u3067 equals() \u3092\u5b9f\u88c5\u3059\u308b\u969b\u306b\u767a\u751f\u3057\u3084\u3059\u3044\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 Point {\n    private int x, y;\n\n    \/\/ \u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u7b49\u306f\u7701\u7565\n\n    @Override\n    public boolean equals(Object o) {\n        if (o instanceof Point) {\n            Point p = (Point) o;\n            return x == p.x &amp;&amp; y == p.y;\n        }\n        return false;\n    }\n}\n\npublic class ColorPoint extends Point {\n    private Color color;\n\n    \/\/ \u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u7b49\u306f\u7701\u7565\n\n    @Override\n    public boolean equals(Object o) {\n        if (!(o instanceof ColorPoint)) return false;\n        return super.equals(o) &amp;&amp; ((ColorPoint) o).color == color;\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-141\">\n<p>\u3053\u306e\u5b9f\u88c5\u3067\u306f\u3001<code>point.equals(colorPoint)<\/code> \u306f true \u3092\u8fd4\u3059\u53ef\u80fd\u6027\u304c\u3042\u308a\u307e\u3059\u304c\u3001<code>colorPoint.equals(point)<\/code> \u306f\u5e38\u306b false \u3092\u8fd4\u3057\u307e\u3059\u3002\u3053\u308c\u306f\u5bfe\u79f0\u6027\u306e\u9055\u53cd\u3067\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-142\">\n<p>\u89e3\u6c7a\u7b56\u3068\u3057\u3066\u3001\u5b8c\u5168\u306b\u5225\u306e\u30af\u30e9\u30b9\u3068\u3057\u3066\u6271\u3046\u304b\u3001\u62bd\u8c61\u30af\u30e9\u30b9\u3092\u4f7f\u7528\u3057\u3066\u3088\u308a\u67d4\u8edf\u306a\u8a2d\u8a08\u3092\u884c\u3046\u3053\u3068\u304c\u8003\u3048\u3089\u308c\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-143\">\n<h3 class=\"wp-block-heading\" id=\"i-37\">\u63a8\u79fb\u6027\u3092\u4fdd\u3064\uff1a\u7d99\u627f\u6642\u306eequals()\u5b9f\u88c5\u306e\u843d\u3068\u3057\u7a74<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-144\">\n<p>\u63a8\u79fb\u6027\u306f\u3001x.equals(y) \u304b\u3064 y.equals(z) \u306e\u5834\u5408\u3001x.equals(z) \u3082 true \u3067\u306a\u3051\u308c\u3070\u306a\u3089\u306a\u3044\u3068\u3044\u3046\u6027\u8cea\u3067\u3059\u3002\u7d99\u627f\u3092\u4f7f\u7528\u3059\u308b\u969b\u306b\u3001\u3053\u306e\u6027\u8cea\u3092\u7dad\u6301\u3059\u308b\u306e\u306f\u96e3\u3057\u3044\u5834\u5408\u304c\u3042\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=\"\">public class Point {\n    private int x, y;\n\n    \/\/ \u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u7b49\u306f\u7701\u7565\n\n    @Override\n    public boolean equals(Object o) {\n        if (!(o instanceof Point)) return false;\n        Point p = (Point) o;\n        return x == p.x &amp;&amp; y == p.y;\n    }\n}\n\npublic class ColorPoint extends Point {\n    private Color color;\n\n    \/\/ \u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u7b49\u306f\u7701\u7565\n\n    @Override\n    public boolean equals(Object o) {\n        if (!(o instanceof Point)) return false;\n        if (!(o instanceof ColorPoint)) return o.equals(this);\n        return super.equals(o) &amp;&amp; ((ColorPoint) o).color == color;\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-145\">\n<p>\u3053\u306e\u5b9f\u88c5\u3067\u306f\u3001\u63a8\u79fb\u6027\u304c\u4fdd\u305f\u308c\u307e\u305b\u3093\u3002<code>ColorPoint cp = new ColorPoint(1, 2, Color.RED);<\/code>\u3001<code>Point p = new Point(1, 2);<\/code>\u3001<code>ColorPoint cp2 = new ColorPoint(1, 2, Color.BLUE);<\/code> \u3068\u3059\u308b\u3068\u3001<code>cp.equals(p)<\/code> \u3068 <code>p.equals(cp2)<\/code> \u306f true \u3067\u3059\u304c\u3001<code>cp.equals(cp2)<\/code> \u306f false \u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-146\">\n<p>\u3053\u306e\u3088\u3046\u306a\u554f\u984c\u3092\u907f\u3051\u308b\u306b\u306f\u3001\u7d99\u627f\u3088\u308a\u3082\u30b3\u30f3\u30dd\u30b8\u30b7\u30e7\u30f3\u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u304c\u63a8\u5968\u3055\u308c\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-147\">\n<h3 class=\"wp-block-heading\" id=\"i-38\">null \u5b89\u5168\u6027\u3068\u4e00\u8cab\u6027\u3092\u4fdd\u3064<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-148\">\n<p>null \u5024\u306e\u9069\u5207\u306a\u51e6\u7406\u3068\u4e00\u8cab\u6027\u306e\u78ba\u4fdd\u306f\u3001\u5805\u7262\u306a equals() \u5b9f\u88c5\u306e\u9375\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=\"\">@Override\npublic boolean equals(Object o) {\n    if (this == o) return true;\n    if (o == null || getClass() != o.getClass()) return false;\n    MyClass myClass = (MyClass) o;\n    return Objects.equals(field1, myClass.field1) &amp;&amp;\n           Objects.equals(field2, myClass.field2);\n}<\/pre>\n\n\n<div id=\"sgb-css-id-149\">\n<p>\u3053\u306e\u5b9f\u88c5\u3067\u306f\u3001null \u30c1\u30a7\u30c3\u30af\u3068\u578b\u30c1\u30a7\u30c3\u30af\u3092\u9069\u5207\u306b\u884c\u3044\u3001Objects.equals() \u3092\u4f7f\u7528\u3057\u3066 null \u306e\u5b89\u5168\u306a\u6bd4\u8f03\u3092\u884c\u3063\u3066\u3044\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-150\">\n<h3 class=\"wp-block-heading\" id=\"i-39\">\u6d6e\u52d5\u5c0f\u6570\u70b9\u6570\u306e\u6bd4\u8f03\u306b\u304a\u3051\u308b\u6ce8\u610f\u70b9<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-151\">\n<p>\u6d6e\u52d5\u5c0f\u6570\u70b9\u6570\uff08float \u3068 double\uff09\u306e\u6bd4\u8f03\u306b\u306f\u7279\u5225\u306a\u6ce8\u610f\u304c\u5fc5\u8981\u3067\u3059\u3002IEEE 754 \u898f\u683c\u306e\u7279\u6027\u306b\u3088\u308a\u3001\u76f4\u63a5\u7684\u306a == \u6bd4\u8f03\u306f\u554f\u984c\u3092\u5f15\u304d\u8d77\u3053\u3059\u53ef\u80fd\u6027\u304c\u3042\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=\"\">public class FloatPoint {\n    private float x, y;\n\n    \/\/ \u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u7b49\u306f\u7701\u7565\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        FloatPoint that = (FloatPoint) o;\n        return Float.compare(that.x, x) == 0 &amp;&amp;\n               Float.compare(that.y, y) == 0;\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-152\">\n<p>Float.compare() \u307e\u305f\u306f Double.compare() \u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u3067\u3001NaN \u3084\u7121\u9650\u5927\u3092\u9069\u5207\u306b\u51e6\u7406\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-153\">\n<h3 class=\"wp-block-heading\" id=\"i-40\">\u914d\u5217\u3068\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u306e\u6bd4\u8f03<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-154\">\n<p>\u914d\u5217\u3084\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u3092\u542b\u3080\u30af\u30e9\u30b9\u306e equals() \u5b9f\u88c5\u3067\u306f\u3001\u5185\u5bb9\u306e\u6bd4\u8f03\u306b\u6ce8\u610f\u304c\u5fc5\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 ArrayContainer {\n    private int[] data;\n\n    \/\/ \u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u7b49\u306f\u7701\u7565\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        ArrayContainer that = (ArrayContainer) o;\n        return Arrays.equals(data, that.data);\n    }\n\n    @Override\n    public int hashCode() {\n        return Arrays.hashCode(data);\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-155\">\n<p>Arrays.equals() \u3084 Objects.deepEquals() \u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u914d\u5217\u306e\u5185\u5bb9\u3092\u9069\u5207\u306b\u6bd4\u8f03\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<h3 class=\"wp-block-heading\" id=\"i-41\">\u5b9f\u88c5\u30df\u30b9\u3068\u305d\u306e\u56de\u907f\u306e\u307e\u3068\u3081<\/h3>\n\n\n<div id=\"sgb-css-id-163\">\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\">equals()\u5b9f\u88c5\u306e\u30c1\u30a7\u30c3\u30af\u30ea\u30b9\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 is-style-sango-list-simple\"><div id=\"sgb-css-id-156\">\n<li>\u53cd\u5c04\u6027\u3001\u5bfe\u79f0\u6027\u3001\u63a8\u79fb\u6027\u3001\u4e00\u8cab\u6027\u3092\u78ba\u4fdd\u3057\u3066\u3044\u308b\u304b<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-157\">\n<li>null \u5024\u3092\u9069\u5207\u306b\u51e6\u7406\u3057\u3066\u3044\u308b\u304b<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-158\">\n<li>hashCode() \u30e1\u30bd\u30c3\u30c9\u3068\u6574\u5408\u6027\u304c\u53d6\u308c\u3066\u3044\u308b\u304b<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-159\">\n<li>\u7d99\u627f\u3092\u4f7f\u7528\u3059\u308b\u5834\u5408\u3001\u63a8\u79fb\u6027\u3092\u7dad\u6301\u3067\u304d\u3066\u3044\u308b\u304b<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-160\">\n<li>\u6d6e\u52d5\u5c0f\u6570\u70b9\u6570\u3092\u9069\u5207\u306b\u6bd4\u8f03\u3057\u3066\u3044\u308b\u304b<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-161\">\n<li>\u914d\u5217\u3084\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u306e\u5185\u5bb9\u3092\u6b63\u3057\u304f\u6bd4\u8f03\u3057\u3066\u3044\u308b\u304b<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-162\">\n<li>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u8003\u616e\u3057\u3001\u6bd4\u8f03\u9806\u5e8f\u3092\u6700\u9069\u5316\u3057\u3066\u3044\u308b\u304b<\/li>\n<\/div><\/ol>\n<\/div><\/div>\n<\/div>\n\n<div id=\"sgb-css-id-164\">\n<p>\u3053\u308c\u3089\u306e\u30dd\u30a4\u30f3\u30c8\u306b\u6ce8\u610f\u3092\u6255\u3046\u3053\u3068\u3067\u3001\u5805\u7262\u3067\u4fe1\u983c\u6027\u306e\u9ad8\u3044 equals() \u5b9f\u88c5\u3092\u4f5c\u6210\u3067\u304d\u307e\u3059\u3002\u307e\u305f\u3001\u5fc5\u8981\u306a\u30e6\u30cb\u30c3\u30c8\u30c6\u30b9\u30c8\u30b1\u30fc\u30b9\u3092\u4f5c\u6210\u3057\u3001\u69d8\u3005\u306a\u30b1\u30fc\u30b9\u3067\u306e\u52d5\u4f5c\u3092\u78ba\u8a8d\u3059\u308b\u3053\u3068\u3082\u91cd\u8981\u3067\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-165\">\n<p>\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u3053\u308c\u307e\u3067\u306e\u5185\u5bb9\u3092\u7dcf\u62ec\u3057\u3001Java \u306b\u304a\u3051\u308b equals() \u306e\u91cd\u8981\u6027\u3068\u4eca\u5f8c\u306e\u5b66\u7fd2\u65b9\u5411\u306b\u3064\u3044\u3066\u8ff0\u3079\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-166\">\n<h2 class=\"wp-block-heading\" id=\"i-42\">8. \u307e\u3068\u3081\uff1a\u5805\u7262\u306aJava\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u958b\u767a\u306b\u5411\u3051\u3066<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-167\">\n<p>\u672c\u8a18\u4e8b\u3067\u306f\u3001Java \u306e <code>equals()<\/code> \u30e1\u30bd\u30c3\u30c9\u306b\u3064\u3044\u3066\u3001\u57fa\u790e\u304b\u3089\u5fdc\u7528\u307e\u3067\u3092\u5e45\u5e83\u304f\u89e3\u8aac\u3057\u3066\u304d\u307e\u3057\u305f\u3002\u9069\u5207\u306b\u5b9f\u88c5\u3055\u308c\u305f <code>equals()<\/code> \u30e1\u30bd\u30c3\u30c9\u306f\u3001\u5805\u7262\u3067\u4fe1\u983c\u6027\u306e\u9ad8\u3044 Java \u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u958b\u767a\u306e\u57fa\u76e4\u3068\u306a\u308a\u307e\u3059\u3002\u3053\u3053\u3067\u3001\u4e3b\u8981\u306a\u30dd\u30a4\u30f3\u30c8\u3092\u632f\u308a\u8fd4\u308a\u3001\u4eca\u5f8c\u306e\u5b66\u7fd2\u3078\u306e\u6307\u91dd\u3092\u63d0\u4f9b\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n\n<h3 class=\"wp-block-heading\" id=\"i-43\">equals()\u30de\u30b9\u30bf\u30fc\u3078\u306e\u9053\uff1a\u6b21\u306e\u30b9\u30c6\u30c3\u30d7\u3068\u5b66\u7fd2\u30ea\u30bd\u30fc\u30b9<\/h3>\n\n\n<div id=\"sgb-css-id-168\">\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\">\u4eca\u5f8c\u306e\u30b9\u30c6\u30c3\u30d7<\/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\">\n<li>\u57fa\u672c\u3092\u62bc\u3055\u3048\u308b\uff1a equals() \u306e\u57fa\u672c\u6982\u5ff5\u3001Object \u30af\u30e9\u30b9\u3067\u306e\u5b9a\u7fa9\u3001\u305d\u3057\u3066\u30aa\u30fc\u30d0\u30fc\u30e9\u30a4\u30c9\u306e\u5fc5\u8981\u6027\u3092\u5341\u5206\u306b\u7406\u89e3\u3059\u308b\u3053\u3068\u304c\u51fa\u767a\u70b9\u3067\u3059\u3002<\/li>\n\n\n\n<li>\u4e00\u822c\u5951\u7d04\u3092\u9075\u5b88\uff1a \u53cd\u5c04\u6027\u3001\u5bfe\u79f0\u6027\u3001\u63a8\u79fb\u6027\u3001\u4e00\u8cab\u6027\u3068\u3044\u3046 equals() \u306e\u4e00\u822c\u5951\u7d04\u3092\u5e38\u306b\u610f\u8b58\u3057\u3001\u3053\u308c\u3089\u3092\u6e80\u305f\u3059\u5b9f\u88c5\u3092\u5fc3\u304c\u3051\u307e\u3057\u3087\u3046\u3002<\/li>\n\n\n\n<li>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u8003\u616e\uff1a \u65e9\u671f\u30ea\u30bf\u30fc\u30f3\u3001\u30d5\u30a3\u30fc\u30eb\u30c9\u6bd4\u8f03\u306e\u9806\u5e8f\u6700\u9069\u5316\u3001hashCode() \u306e\u30ad\u30e3\u30c3\u30b7\u30f3\u30b0\u306a\u3069\u3001\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u610f\u8b58\u3057\u305f\u5b9f\u88c5\u30c6\u30af\u30cb\u30c3\u30af\u3092\u7fd2\u5f97\u3057\u307e\u3057\u3087\u3046\u3002<\/li>\n\n\n\n<li>\u3088\u304f\u3042\u308b\u30df\u30b9\u3092\u907f\u3051\u308b\uff1a \u7d99\u627f\u6642\u306e\u6ce8\u610f\u70b9\u3001\u6d6e\u52d5\u5c0f\u6570\u70b9\u6570\u306e\u6bd4\u8f03\u3001null \u5024\u306e\u51e6\u7406\u306a\u3069\u3001\u4e00\u822c\u7684\u306a\u30df\u30b9\u3092\u7406\u89e3\u3057\u3001\u56de\u907f\u3059\u308b\u65b9\u6cd5\u3092\u8eab\u306b\u3064\u3051\u307e\u3057\u3087\u3046\u3002<\/li>\n\n\n\n<li>\u6700\u65b0\u306e\u6a5f\u80fd\u3092\u6d3b\u7528\uff1a Java 7 \u4ee5\u964d\u3067\u5c0e\u5165\u3055\u308c\u305f Objects.equals() \u3084 Objects.hash() \u306a\u3069\u306e\u6a5f\u80fd\u3092\u7a4d\u6975\u7684\u306b\u6d3b\u7528\u3057\u3001\u3088\u308a\u5805\u7262\u3067\u7c21\u6f54\u306a\u5b9f\u88c5\u3092\u76ee\u6307\u3057\u307e\u3057\u3087\u3046\u3002<\/li>\n\n\n\n<li>\u95a2\u9023\u6982\u5ff5\u3092\u5b66\u3076\uff1a Comparable \u30a4\u30f3\u30bf\u30fc\u30d5\u30a7\u30fc\u30b9\u3001hashCode() \u30e1\u30bd\u30c3\u30c9\u3001\u305d\u3057\u3066\u5404\u7a2e\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u30af\u30e9\u30b9\u3068\u306e\u95a2\u9023\u6027\u3092\u7406\u89e3\u3059\u308b\u3053\u3068\u3067\u3001\u3088\u308a\u6df1\u3044\u77e5\u8b58\u3092\u5f97\u3089\u308c\u307e\u3059\u3002<\/li>\n\n\n\n<li>\u5b9f\u8df5\u3068\u30ec\u30d3\u30e5\u30fc\uff1a \u5b66\u3093\u3060\u77e5\u8b58\u3092\u5b9f\u969b\u306e\u30d7\u30ed\u30b8\u30a7\u30af\u30c8\u306b\u9069\u7528\u3057\u3001\u30e1\u30f3\u30d0\u3068\u306e\u30b3\u30fc\u30c9\u30ec\u30d3\u30e5\u30fc\u3092\u901a\u3058\u3066\u5b9f\u88c5\u3092\u78e8\u3044\u3066\u3044\u304d\u307e\u3057\u3087\u3046\u3002<\/li>\n<\/ol>\n<\/div><\/div>\n<\/div>\n\n<div id=\"sgb-css-id-169\">\n<p>\u3053\u308c\u3089\u306e\u30b9\u30c6\u30c3\u30d7\u3092\u8e0f\u3080\u3053\u3068\u3067\u3001<code>equals()<\/code> \u306e\u30de\u30b9\u30bf\u30fc\u3078\u306e\u9053\u3092\u7740\u5b9f\u306b\u9032\u3080\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-170\">\n<p>\u3088\u308a\u6df1\u3044\u5b66\u7fd2\u306e\u305f\u3081\u306b\u3001\u4ee5\u4e0b\u306e\u30ea\u30bd\u30fc\u30b9\u3092\u304a\u3059\u3059\u3081\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\">\u5b66\u7fd2\u306e\u30ea\u30bd\u30fc\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-171\">\n<li>\u66f8\u7c4d\uff1a\u300cEffective Java\u300d\uff08Joshua Bloch\u8457\uff09- \u7279\u306b\u7b2c3\u7248\u306e\u9805\u76ee10\u300cequals \u30e1\u30bd\u30c3\u30c9\u3092\u4e0a\u66f8\u304d\u3059\u308b\u3068\u304d\u306f\u4e00\u822c\u5951\u7d04\u306b\u5f93\u3046\u300d\u3092\u53c2\u7167\u3002<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-172\">\n<li>\u30aa\u30f3\u30e9\u30a4\u30f3\u30b3\u30fc\u30b9\uff1aCoursera \u306e\u300cObject Oriented Java Programming: Data Structures and Beyond\u300d\u30b7\u30ea\u30fc\u30ba<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-173\">\n<li>\u6280\u8853\u6587\u66f8\uff1aOracle \u306e Java Documentation\u3001\u7279\u306b Object \u30af\u30e9\u30b9\u306e\u516c\u5f0f\u30c9\u30ad\u30e5\u30e1\u30f3\u30c8<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-174\">\n<li>\u30b3\u30df\u30e5\u30cb\u30c6\u30a3\uff1aStack Overflow \u306e [java] [equals] \u30bf\u30b0\u4ed8\u304d\u306e\u8cea\u554f\u3092\u53c2\u7167<\/li>\n<\/div><\/ol>\n<\/div><\/div>\n\n\n<div id=\"sgb-css-id-175\">\n<h3 class=\"wp-block-heading\" id=\"i-44\">\u5c06\u6765\u3092\u898b\u636e\u3048\u3066<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-176\">\n<p>Java \u8a00\u8a9e\u3068\u30a8\u30b3\u30b7\u30b9\u30c6\u30e0\u306f\u5e38\u306b\u9032\u5316\u3057\u3066\u3044\u307e\u3059\u3002\u4eca\u5f8c\u3001<code>equals()<\/code> \u306e\u5b9f\u88c5\u306b\u5f71\u97ff\u3092\u4e0e\u3048\u308b\u53ef\u80fd\u6027\u306e\u3042\u308b\u52d5\u5411\u3068\u3057\u3066\u4ee5\u4e0b\u304c\u6319\u3052\u3089\u308c\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-180\">\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\"><code>equals()<\/code> \u306e\u52d5\u5411<\/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-177\">\n<li>Pattern Matching\uff1a Java 14\u3067\u5c0e\u5165\u3055\u308c\u305f\u30d1\u30bf\u30fc\u30f3\u30de\u30c3\u30c1\u30f3\u30b0\u6a5f\u80fd\u304c\u3001\u5c06\u6765\u7684\u306b <code>equals()<\/code> \u306e\u5b9f\u88c5\u3092\u3088\u308a\u7c21\u6f54\u306b\u3059\u308b\u53ef\u80fd\u6027\u304c\u3042\u308a\u307e\u3059\u3002<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-178\">\n<li>Value Types\uff1a Project Valhalla \u306e\u4e00\u90e8\u3068\u3057\u3066\u691c\u8a0e\u3055\u308c\u3066\u3044\u308b Value Types \u304c\u5c0e\u5165\u3055\u308c\u308c\u3070\u3001<code>equals()<\/code> \u306e\u6271\u3044\u304c\u5927\u304d\u304f\u5909\u308f\u308b\u53ef\u80fd\u6027\u304c\u3042\u308a\u307e\u3059\u3002<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-179\">\n<li>\u81ea\u52d5\u751f\u6210\u30c4\u30fc\u30eb\u306e\u9032\u5316\uff1a IDE\u3084\u30d3\u30eb\u30c9\u30c4\u30fc\u30eb\u306e\u767a\u5c55\u306b\u3088\u308a\u3001\u3088\u308a\u6d17\u7df4\u3055\u308c\u305f <code>equals()<\/code> \u306e\u81ea\u52d5\u751f\u6210\u304c\u53ef\u80fd\u306b\u306a\u308b\u304b\u3082\u3057\u308c\u307e\u305b\u3093\u3002<\/li>\n<\/div><\/ol>\n<\/div><\/div>\n<\/div>\n\n<div id=\"sgb-css-id-181\">\n<p>\u3053\u308c\u3089\u306e\u52d5\u5411\u306b\u6ce8\u76ee\u3057\u3064\u3064\u3001\u57fa\u672c\u7684\u306a\u539f\u5247\u3068\u6700\u65b0\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\u3092\u30d0\u30e9\u30f3\u30b9\u826f\u304f\u5b66\u3073\u7d9a\u3051\u308b\u3053\u3068\u304c\u91cd\u8981\u3067\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-182\">\n<h3 class=\"wp-block-heading\" id=\"i-45\">\u6700\u5f8c\u306b<\/h3>\n<\/div>\n\n\n<p><code>equals()<\/code> \u30e1\u30bd\u30c3\u30c9\u306f\u3001\u4e00\u898b\u5358\u7d14\u306b\u898b\u3048\u3066\u5965\u304c\u6df1\u3044 Java \u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u306e\u8981\u7d20\u3067\u3059\u3002\u9069\u5207\u306b\u5b9f\u88c5\u3059\u308b\u3053\u3068\u3067\u3001\u30d0\u30b0\u306e\u5c11\u306a\u3044\u3001\u4e88\u6e2c\u53ef\u80fd\u306a\u52d5\u4f5c\u3092\u3059\u308b\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3092\u958b\u767a\u3067\u304d\u307e\u3059\u3002\u672c\u8a18\u4e8b\u3067\u5b66\u3093\u3060\u77e5\u8b58\u3092\u57fa\u306b\u3001\u305c\u3072\u81ea\u8eab\u306e\u30b3\u30fc\u30c9\u3092\u898b\u76f4\u3057\u3001\u6539\u5584\u3092\u56f3\u3063\u3066\u307f\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n\n\n\n<p>\u5805\u7262\u306a <code>equals()<\/code> \u5b9f\u88c5\u306f\u3001\u5805\u7262\u306a Java \u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u958b\u767a\u3078\u306e\u7b2c\u4e00\u6b69\u3067\u3059\u3002\u3053\u306e\u57fa\u790e\u3092\u3057\u3063\u304b\u308a\u3068\u56fa\u3081\u308b\u3053\u3068\u3067\u3001\u3088\u308a\u9ad8\u5ea6\u306a Java \u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u3078\u306e\u9053\u304c\u958b\u3051\u308b\u3067\u3057\u3087\u3046\u3002\u7d99\u7d9a\u7684\u306a\u5b66\u7fd2\u3068\u5b9f\u8df5\u3092\u901a\u3058\u3066\u3001Java \u30de\u30b9\u30bf\u30fc\u3078\u306e\u9053\u3092\u6b69\u3093\u3067\u3044\u304d\u307e\u3057\u3087\u3046\u3002<\/p>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Warning: Undefined array key &#8220;is_admin&#8221; in \/home\/xs392991\/dexall.co.jp\/public_html\/articles\/wp-content\/themes\/ &#8230; 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