{"id":729,"date":"2024-11-15T14:52:42","date_gmt":"2024-11-15T05:52:42","guid":{"rendered":"https:\/\/dexall.co.jp\/articles\/?p=729"},"modified":"2025-03-24T08:52:53","modified_gmt":"2025-03-23T23:52:53","slug":"%e3%80%90java%e5%85%a5%e9%96%80%e3%80%91%e6%96%87%e5%ad%97%e5%88%97%e6%af%94%e8%bc%83%e3%81%ae%e6%b1%ba%e5%ae%9a%e7%89%88%ef%bc%81equals%e3%81%a8%e3%81%ae%e9%81%95%e3%81%84%e3%81%8b%e3%82%89","status":"publish","type":"post","link":"https:\/\/dexall.co.jp\/articles\/?p=729","title":{"rendered":"\u3010Java\u5165\u9580\u3011\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u6c7a\u5b9a\u7248\uff01equals\u3068==\u306e\u9055\u3044\u304b\u3089\u5b9f\u8df5\u7684\u306a\u4f7f\u3044\u65b9\u307e\u3067\u89e3\u8aac"},"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\">\uff11\uff0eJava\u3067\u306e\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u57fa\u790e\u77e5\u8b58<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-2\">1.1 \u6587\u5b57\u5217\u3092\u30d7\u30ed\u30b0\u30e9\u30e0\u3067\u6bd4\u8f03\u3059\u308b\u5fc5\u8981\u6027<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-3\">1.2 Java\u306e\u6587\u5b57\u5217\u6bd4\u8f03\u3067\u4f7f\u3048\u308b\u4e3b\u306a\u30e1\u30bd\u30c3\u30c9<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-4\">\uff12\uff0eequals()\u30e1\u30bd\u30c3\u30c9\u3068\u6f14\u7b97\u5b50==\u306e\u6c7a\u5b9a\u7684\u306a\u9055\u3044<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-5\">2.1 equals()\u30e1\u30bd\u30c3\u30c9\u304c\u6587\u5b57\u5217\u306e\u5185\u5bb9\u3092\u6bd4\u8f03\u3059\u308b\u4ed5\u7d44\u307f<\/a>      <\/li>      <li>        <a href=\"#i-6\">2.2 \u6f14\u7b97\u5b50==\u304c\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u53c2\u7167\u3092\u6bd4\u8f03\u3059\u308b\u4ed5\u7d44\u307f<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-7\">2.3 \u8aa4\u3063\u305f\u6bd4\u8f03\u65b9\u6cd5\u306b\u3088\u308b\u6df1\u523b\u306a\u30d0\u30b0\u4e8b\u4f8b<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-8\">\uff13\uff0e\u52b9\u7387\u7684\u306a\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u5b9f\u8df5\u30c6\u30af\u30cb\u30c3\u30af<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-9\">3.1 \u5927\u6587\u5b57\u5c0f\u6587\u5b57\u3092\u533a\u5225\u3057\u306a\u3044\u6bd4\u8f03\u65b9\u6cd5<\/a>      <\/li>      <li>        <a href=\"#i-10\">3.2 null\u30bb\u30fc\u30d5\u306a\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u5b9f\u88c5\u65b9\u6cd5<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-11\">3.3 \u8907\u6570\u306e\u6587\u5b57\u5217\u3092\u52b9\u7387\u7684\u306b\u6bd4\u8f03\u3059\u308b\u30c6\u30af\u30cb\u30c3\u30af<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-12\">\uff14\uff0e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u8003\u616e\u3057\u305f\u6587\u5b57\u5217\u6bd4\u8f03<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-13\">4.1 String.intern()\u30e1\u30bd\u30c3\u30c9\u3092\u6d3b\u7528\u3057\u305f\u6700\u9069\u5316<\/a>      <\/li>      <li>        <a href=\"#i-14\">4.2 \u5927\u91cf\u306e\u6587\u5b57\u5217\u6bd4\u8f03\u6642\u306e\u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u306e\u524a\u6e1b\u65b9\u6cd5<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-15\">4.3 \u6587\u5b57\u5217\u6bd4\u8f03\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u8a08\u6e2c\u3068\u6539\u5584<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-16\">\uff15\uff0e\u5b9f\u8df5\u7684\u306a\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-17\">5.1 \u53ef\u8aad\u6027\u306e\u9ad8\u3044\u6587\u5b57\u5217\u6bd4\u8f03\u30b3\u30fc\u30c9\u306e\u66f8\u304d\u65b9<\/a>      <\/li>      <li>        <a href=\"#i-18\">5.2 \u30e6\u30cb\u30c3\u30c8\u30c6\u30b9\u30c8\u3067\u306e\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u691c\u8a3c\u65b9\u6cd5<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-19\">5.3 \u30bb\u30ad\u30e5\u30ea\u30c6\u30a3\u3092\u8003\u616e\u3057\u305f\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u5b9f\u88c5<\/a>      <\/li>    <\/ul>  <\/li>  <li class=\"last\">    <a href=\"#i-20\">\u307e\u3068\u3081\uff1a\u52b9\u679c\u7684\u306a\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u5b9f\u8df5\u30ac\u30a4\u30c9<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-21\">\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u9078\u629e\u30d5\u30ed\u30fc\u30c1\u30e3\u30fc\u30c8<\/a>      <\/li>      <li>        <a href=\"#i-22\">\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\u30c1\u30a7\u30c3\u30af\u30ea\u30b9\u30c8<\/a>      <\/li>      <li>        <a href=\"#i-23\">\u6b21\u306e\u30b9\u30c6\u30c3\u30d7<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-24\">\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\u3067\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u3092\u59cb\u3081\u305f\u591a\u304f\u306e\u958b\u767a\u8005\u304c\u3001\u6587\u5b57\u5217\u6bd4\u8f03\u3067\u601d\u308f\u306c\u3064\u307e\u305a\u304d\u3092\u7d4c\u9a13\u3057\u307e\u3059\u3002\u7279\u306b <code>equals()<\/code> \u30e1\u30bd\u30c3\u30c9\u3068 <code>==<\/code> \u6f14\u7b97\u5b50\u306e\u9055\u3044\u306f\u3001\u521d\u5b66\u8005\u304c\u3088\u304f\u6df7\u4e71\u3059\u308b\u30dd\u30a4\u30f3\u30c8\u306e\u4e00\u3064\u3067\u3059\u3002\u3053\u306e\u8a18\u4e8b\u3067\u306f\u3001Java \u306b\u304a\u3051\u308b\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u57fa\u790e\u304b\u3089\u5b9f\u8df5\u7684\u306a\u30c6\u30af\u30cb\u30c3\u30af\u3001\u3055\u3089\u306b\u306f\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3068\u30bb\u30ad\u30e5\u30ea\u30c6\u30a3\u307e\u3067\u3001\u4f53\u7cfb\u7684\u306b\u89e3\u8aac\u3057\u3066\u3044\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-7\">\n<div class=\"wp-block-sgb-block-simple sgb-box-simple sgb-box-simple--title-normal sgb-box-simple--with-border\"><div style=\"background-color:var(--wp--preset--color--sango-main);color:#FFF\" class=\"sgb-box-simple__title\">\u672c\u8a18\u4e8b\u3067\u5b66\u3079\u308b\u3053\u3068<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ul class=\"wp-block-list\"><div id=\"sgb-css-id-3\">\n<li>\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u57fa\u672c\u7684\u306a\u65b9\u6cd5\u3068\u4ed5\u7d44\u307f<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-4\">\n<li><code>equals()<\/code>\u30e1\u30bd\u30c3\u30c9\u3068==\u6f14\u7b97\u5b50\u306e\u660e\u78ba\u306a\u9055\u3044<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-5\">\n<li>\u52b9\u7387\u7684\u306a\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u5b9f\u88c5\u30c6\u30af\u30cb\u30c3\u30af<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-6\">\n<li>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u8003\u616e\u3057\u305f\u6700\u9069\u5316\u65b9\u6cd5<\/li>\n<\/div>\n\n\n<li>\u30bb\u30ad\u30e5\u30a2\u306a\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u5b9f\u88c5\u65b9\u6cd5<\/li>\n<\/ul>\n<\/div><\/div>\n<\/div>\n\n<div id=\"sgb-css-id-8\">\n<p>\u6587\u5b57\u5217\u6bd4\u8f03\u306f\u4e00\u898b\u5358\u7d14\u306a\u51e6\u7406\u306b\u898b\u3048\u307e\u3059\u304c\u3001\u5b9f\u969b\u306e\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u958b\u767a\u3067\u306f\u69d8\u3005\u306a\u8003\u616e\u304c\u5fc5\u8981\u306b\u306a\u308a\u307e\u3059\u3002\u3053\u306e\u8a18\u4e8b\u3067\u306f\u3001\u5358\u306a\u308b\u6bd4\u8f03\u65b9\u6cd5\u306e\u89e3\u8aac\u306b\u3068\u3069\u307e\u3089\u305a\u3001\u5b9f\u8df5\u7684\u306a\u30b3\u30fc\u30c9\u4f8b\u3068\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\u3092\u4ea4\u3048\u306a\u304c\u3089\u3001\u30d7\u30ed\u30c0\u30af\u30b7\u30e7\u30f3\u74b0\u5883\u3067\u4f7f\u3048\u308b\u77e5\u8b58\u3092\u63d0\u4f9b\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-9\">\n<p>\u5b9f\u8df5\u7684\u306a\u30b3\u30fc\u30c9\u4f8b\u3068\u5171\u306b\u3001\u6bb5\u968e\u7684\u306b\u7406\u89e3\u3092\u6df1\u3081\u3066\u3044\u304d\u307e\u3057\u3087\u3046\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-10\">\n<h2 class=\"wp-block-heading\" id=\"i-1\">\uff11\uff0eJava\u3067\u306e\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u57fa\u790e\u77e5\u8b58<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-11\">\n<h3 class=\"wp-block-heading\" id=\"i-2\">1.1 \u6587\u5b57\u5217\u3092\u30d7\u30ed\u30b0\u30e9\u30e0\u3067\u6bd4\u8f03\u3059\u308b\u5fc5\u8981\u6027<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-12\">\n<p>\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u306b\u304a\u3044\u3066\u6587\u5b57\u5217\u6bd4\u8f03\u306f\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u69d8\u3005\u306a\u5834\u9762\u3067\u5fc5\u8981\u4e0d\u53ef\u6b20\u306a\u64cd\u4f5c\u3067\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-13\">\n<p>\u3000\u25cf <strong>\u30e6\u30fc\u30b6\u30fc\u8a8d\u8a3c<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-14\">\n<p>\u3000\u3000\u25cf \u30e6\u30fc\u30b6\u30fc\u540d\u3084\u30d1\u30b9\u30ef\u30fc\u30c9\u306e\u7167\u5408<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-15\">\n<p>\u3000\u3000\u25cf \u30a2\u30af\u30bb\u30b9\u6a29\u9650\u306e\u78ba\u8a8d<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-16\">\n<p>\u3000\u25cf <strong>\u30c7\u30fc\u30bf\u691c\u8a3c<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-17\">\n<p>\u3000\u3000\u25cf \u5165\u529b\u5024\u306e\u59a5\u5f53\u6027\u30c1\u30a7\u30c3\u30af<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-18\">\n<p>\u3000\u3000\u25cf \u7279\u5b9a\u306e\u6587\u5b57\u5217\u30d1\u30bf\u30fc\u30f3\u306e\u691c\u51fa<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-19\">\n<p>\u3000\u25cf <strong>\u30c7\u30fc\u30bf\u51e6\u7406<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-20\">\n<p>\u3000\u3000\u25cf \u6587\u5b57\u5217\u306e\u4e26\u3073\u66ff\u3048<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-21\">\n<p>\u3000\u3000\u25cf \u91cd\u8907\u30c7\u30fc\u30bf\u306e\u9664\u5916<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-22\">\n<p>\u3000\u25cf <strong>\u5236\u5fa1\u30d5\u30ed\u30fc<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-23\">\n<p>\u3000\u3000\u25cf \u6761\u4ef6\u5206\u5c90\u3067\u306e\u6587\u5b57\u5217\u5224\u5b9a<\/p>\n<\/div>\n\n\n<p>\u3000\u3000\u25cf \u72b6\u614b\u7ba1\u7406\u3067\u306e\u6587\u5b57\u5217\u6bd4\u8f03<\/p>\n\n\n<div id=\"sgb-css-id-24\">\n<p>\u4ee5\u4e0b\u306f\u3001\u6587\u5b57\u5217\u6bd4\u8f03\u304c\u5fc5\u8981\u3068\u306a\u308b\u5178\u578b\u7684\u306a\u30b3\u30fc\u30c9\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 LoginValidator {\n    private static final String ADMIN_USERNAME = \"admin\";\n\n    public boolean validateUser(String inputUsername) {\n        \/\/ \u30e6\u30fc\u30b6\u30fc\u540d\u306e\u6bd4\u8f03\u306b\u3088\u308b\u8a8d\u8a3c\n        return ADMIN_USERNAME.equals(inputUsername);\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-25\">\n<h3 class=\"wp-block-heading\" id=\"i-3\">1.2 Java\u306e\u6587\u5b57\u5217\u6bd4\u8f03\u3067\u4f7f\u3048\u308b\u4e3b\u306a\u30e1\u30bd\u30c3\u30c9<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-26\">\n<p>Java\u3067\u306f\u3001\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u305f\u3081\u306b\u8907\u6570\u306e\u30e1\u30bd\u30c3\u30c9\u304c\u7528\u610f\u3055\u308c\u3066\u3044\u307e\u3059\u3002\u72b6\u6cc1\u306b\u5fdc\u3058\u3066\u9069\u5207\u306a\u30e1\u30bd\u30c3\u30c9\u3092\u9078\u629e\u3059\u308b\u3053\u3068\u304c\u91cd\u8981\u3067\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"id-1c5f1fb9-7362-405e-9e0f-6de45ce61fb1\"><div id=\"sgb-css-id-27\">\n<figure class=\"wp-block-table\"><table><thead><tr><th>\u30e1\u30bd\u30c3\u30c9<\/th><th>\u7528\u9014<\/th><th>\u7279\u5fb4<\/th><\/tr><\/thead><tbody><tr><td><code>equals()<\/code><\/td><td>\u6587\u5b57\u5217\u306e\u5185\u5bb9\u3092\u6bd4\u8f03<\/td><td>\u5927\u6587\u5b57\u5c0f\u6587\u5b57\u3092\u533a\u5225\u3059\u308b<\/td><\/tr><tr><td><code>equalsIgnoreCase()<\/code><\/td><td>\u6587\u5b57\u5217\u306e\u5185\u5bb9\u3092\u6bd4\u8f03<\/td><td>\u5927\u6587\u5b57\u5c0f\u6587\u5b57\u3092\u533a\u5225\u3057\u306a\u3044<\/td><\/tr><tr><td><code>compareTo()<\/code><\/td><td>\u6587\u5b57\u5217\u306e\u9806\u5e8f\u3092\u6bd4\u8f03<\/td><td>\u8f9e\u66f8\u9806\u3067\u306e\u6bd4\u8f03\u304c\u53ef\u80fd<\/td><\/tr><tr><td><code>startsWith()<\/code><\/td><td>\u524d\u65b9\u4e00\u81f4\u306e\u78ba\u8a8d<\/td><td>\u7279\u5b9a\u306e\u6587\u5b57\u5217\u3067\u59cb\u307e\u308b\u304b\u30c1\u30a7\u30c3\u30af<\/td><\/tr><tr><td><code>endsWith()<\/code><\/td><td>\u5f8c\u65b9\u4e00\u81f4\u306e\u78ba\u8a8d<\/td><td>\u7279\u5b9a\u306e\u6587\u5b57\u5217\u3067\u7d42\u308f\u308b\u304b\u30c1\u30a7\u30c3\u30af<\/td><\/tr><tr><td><code>contains()<\/code><\/td><td>\u90e8\u5206\u6587\u5b57\u5217\u306e\u5305\u542b\u78ba\u8a8d<\/td><td>\u7279\u5b9a\u306e\u6587\u5b57\u5217\u3092\u542b\u3080\u304b\u30c1\u30a7\u30c3\u30af<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div><\/div>\n\n<div id=\"sgb-css-id-28\">\n<p>\u3053\u308c\u3089\u306e\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u7528\u3057\u305f\u5b9f\u8df5\u7684\u306a\u30b3\u30fc\u30c9\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=\"\">public class StringComparisonExample {\n    public static void main(String[] args) {\n        String str1 = \"Hello, Java\";\n        String str2 = \"hello, java\";\n        String str3 = \"Hello, Java\";\n\n        \/\/ 1. equals()\u306b\u3088\u308b\u53b3\u5bc6\u306a\u6bd4\u8f03\n        System.out.println(str1.equals(str2));  \/\/ false\uff08\u5927\u6587\u5b57\u5c0f\u6587\u5b57\u304c\u7570\u306a\u308b\uff09\n        System.out.println(str1.equals(str3));  \/\/ true\uff08\u5b8c\u5168\u306b\u4e00\u81f4\uff09\n\n        \/\/ 2. equalsIgnoreCase()\u306b\u3088\u308b\u5927\u6587\u5b57\u5c0f\u6587\u5b57\u3092\u533a\u5225\u3057\u306a\u3044\u6bd4\u8f03\n        System.out.println(str1.equalsIgnoreCase(str2));  \/\/ true\n\n        \/\/ 3. compareTo()\u306b\u3088\u308b\u9806\u5e8f\u6bd4\u8f03\n        System.out.println(str1.compareTo(str3));  \/\/ 0\uff08\u7b49\u3057\u3044\uff09\n        System.out.println(\"Apple\".compareTo(\"Banana\"));  \/\/ \u8ca0\u306e\u5024\uff08Apple\u306e\u65b9\u304c\u524d\uff09\n\n        \/\/ 4. \u90e8\u5206\u4e00\u81f4\u306e\u78ba\u8a8d\n        System.out.println(str1.startsWith(\"Hello\"));  \/\/ true\n        System.out.println(str1.endsWith(\"Java\"));     \/\/ true\n        System.out.println(str1.contains(\"Java\"));     \/\/ true\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-29\">\n<p>\u3053\u306e\u30b3\u30fc\u30c9\u306f\u4ee5\u4e0b\u306e\u70b9\u3067\u7279\u306b\u6ce8\u610f\u304c\u5fc5\u8981\u3067\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-30\">\n<p>\u30001. <code>equals()<\/code>\u3068<code>equalsIgnoreCase()<\/code>\u306e\u4f7f\u3044\u5206\u3051<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-31\">\n<p>\u3000\u3000\u25cf \u30e6\u30fc\u30b6\u30fc\u5165\u529b\u306e\u6bd4\u8f03\u3067\u306f<code>equalsIgnoreCase()<\/code>\u304c\u4fbf\u5229<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-32\">\n<p>\u3000\u3000\u25cf \u30b7\u30b9\u30c6\u30e0\u5185\u90e8\u3067\u306e\u53b3\u5bc6\u306a\u6bd4\u8f03\u306b\u306f<code>equals()<\/code>\u3092\u4f7f\u7528<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-33\">\n<p>\u30002. <code>compareTo()<\/code>\u306e\u623b\u308a\u5024\u306e\u89e3\u91c8<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-34\">\n<p>\u3000\u3000\u25cf 0\uff1a\u7b49\u3057\u3044<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-35\">\n<p>\u3000\u3000\u25cf \u8ca0\u306e\u5024\uff1a\u547c\u3073\u51fa\u3057\u5143\u306e\u65b9\u304c\u8f9e\u66f8\u9806\u3067\u524d<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-36\">\n<p>\u3000\u3000\u25cf \u6b63\u306e\u5024\uff1a\u5f15\u6570\u306e\u65b9\u304c\u8f9e\u66f8\u9806\u3067\u524d<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-37\">\n<p>\u30003. \u90e8\u5206\u4e00\u81f4\u30e1\u30bd\u30c3\u30c9\u306e\u4f7f\u7528\u5834\u9762<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-38\">\n<p>\u3000\u3000\u25cf <code>startsWith()<\/code>\uff1a\u30d7\u30ec\u30d5\u30a3\u30c3\u30af\u30b9\u306e\u30c1\u30a7\u30c3\u30af<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-39\">\n<p>\u3000\u3000\u25cf <code>endsWith()<\/code>\uff1a\u30d5\u30a1\u30a4\u30eb\u62e1\u5f35\u5b50\u306e\u78ba\u8a8d<\/p>\n<\/div>\n\n\n<p>\u3000\u3000\u25cf <code>contains()<\/code>\uff1a\u30ad\u30fc\u30ef\u30fc\u30c9\u691c\u7d22<\/p>\n\n\n<div id=\"sgb-css-id-40\">\n<p>\u3053\u308c\u3089\u306e\u30e1\u30bd\u30c3\u30c9\u3092\u9069\u5207\u306b\u4f7f\u3044\u5206\u3051\u308b\u3053\u3068\u3067\u3001\u3088\u308a\u5805\u7262\u3067\u4fdd\u5b88\u6027\u306e\u9ad8\u3044\u30b3\u30fc\u30c9\u3092\u66f8\u304f\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-41\">\n<h2 class=\"wp-block-heading\" id=\"i-4\">\uff12\uff0eequals()\u30e1\u30bd\u30c3\u30c9\u3068\u6f14\u7b97\u5b50==\u306e\u6c7a\u5b9a\u7684\u306a\u9055\u3044<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-42\">\n<h3 class=\"wp-block-heading\" id=\"i-5\">2.1 equals()\u30e1\u30bd\u30c3\u30c9\u304c\u6587\u5b57\u5217\u306e\u5185\u5bb9\u3092\u6bd4\u8f03\u3059\u308b\u4ed5\u7d44\u307f<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-43\">\n<p><code>equals()<\/code>\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u6587\u5b57\u5217\u306e\u5185\u5bb9\uff08\u5024\uff09\u3092\u6bd4\u8f03\u3059\u308b\u65b9\u6cd5\u3068\u3057\u3066\u6700\u3082\u4e00\u822c\u7684\u3067\u5b89\u5168\u306a\u65b9\u6cd5\u3067\u3059\u3002\u3053\u306e\u30e1\u30bd\u30c3\u30c9\u306e\u5185\u90e8\u3067\u306f\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u51e6\u7406\u304c\u884c\u308f\u308c\u3066\u3044\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-44\">\n<p>\u30001. <strong>\u6587\u5b57\u5217\u306e\u9577\u3055\u30c1\u30a7\u30c3\u30af<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-45\">\n<p>\u3000\u3000\u25cf \u307e\u305a\u3001\u6bd4\u8f03\u5bfe\u8c61\u306e\u6587\u5b57\u5217\u9577\u304c\u540c\u3058\u304b\u3092\u78ba\u8a8d<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-46\">\n<p>\u3000\u3000\u25cf \u7570\u306a\u308c\u3070\u5373\u5ea7\u306b<code>false<\/code>\u3092\u8fd4\u3059<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-47\">\n<p>\u30002. <strong>\u6587\u5b57\u306e\u9806\u6b21\u6bd4\u8f03<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-48\">\n<p>\u3000\u3000\u25cf \u5404\u4f4d\u7f6e\u306e\u6587\u5b57\u30921\u3064\u305a\u3064\u6bd4\u8f03<\/p>\n<\/div>\n\n\n<p>\u3000\u3000\u25cf 1\u6587\u5b57\u3067\u3082\u7570\u306a\u308c\u3070<code>false<\/code>\u3092\u8fd4\u3059<\/p>\n\n\n<div id=\"sgb-css-id-49\">\n<p>\u4ee5\u4e0b\u306f<code>equals()<\/code>\u30e1\u30bd\u30c3\u30c9\u306e\u4f7f\u7528\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 EqualsExample {\n    public static void main(String[] args) {\n        String str1 = new String(\"Hello\");\n        String str2 = new String(\"Hello\");\n\n        \/\/ \u6587\u5b57\u5217\u306e\u5185\u5bb9\u3092\u6bd4\u8f03\n        boolean result = str1.equals(str2);  \/\/ true\n\n        \/\/ null\u5b89\u5168\u306a\u6bd4\u8f03\n        String str3 = null;\n        boolean safeResult = \"Hello\".equals(str3);  \/\/ false\n        \/\/ \u6ce8\u610f: str3.equals(\"Hello\") \u306fNullPointerException\u3092\u767a\u751f\u3055\u305b\u308b\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-50\">\n<h3 class=\"wp-block-heading\" id=\"i-6\">2.2 \u6f14\u7b97\u5b50==\u304c\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u53c2\u7167\u3092\u6bd4\u8f03\u3059\u308b\u4ed5\u7d44\u307f<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-51\">\n<p>\u6f14\u7b97\u5b50<code>==<\/code>\u306f\u3001\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u53c2\u7167\uff08\u30e1\u30e2\u30ea\u4e0a\u306e\u30a2\u30c9\u30ec\u30b9\uff09\u3092\u6bd4\u8f03\u3057\u307e\u3059\u3002\u3053\u308c\u306f\u6587\u5b57\u5217\u306e\u5185\u5bb9\u304c\u540c\u3058\u3067\u3082\u3001\u7570\u306a\u308b\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3067\u3042\u308c\u3070<code>false<\/code>\u3092\u8fd4\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 ReferenceComparisonExample {\n    public static void main(String[] args) {\n        \/\/ \u6587\u5b57\u5217\u30ea\u30c6\u30e9\u30eb\u306e\u5834\u5408\n        String str1 = \"Hello\";  \/\/ String Pool\u304b\u3089\u53c2\u7167\n        String str2 = \"Hello\";  \/\/ \u540c\u3058String Pool\u306e\u6587\u5b57\u5217\u3092\u53c2\u7167\n        System.out.println(str1 == str2);  \/\/ true\n\n        \/\/ new\u306b\u3088\u308b\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u751f\u6210\u306e\u5834\u5408\n        String str3 = new String(\"Hello\");  \/\/ \u65b0\u3057\u3044\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u751f\u6210\n        String str4 = new String(\"Hello\");  \/\/ \u5225\u306e\u65b0\u3057\u3044\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u751f\u6210\n        System.out.println(str3 == str4);  \/\/ false\n\n        \/\/ intern()\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u7528\u3057\u305f\u5834\u5408\n        String str5 = str3.intern();  \/\/ String Pool\u306e\u53c2\u7167\u3092\u53d6\u5f97\n        String str6 = \"Hello\";        \/\/ \u540c\u3058String Pool\u306e\u53c2\u7167\n        System.out.println(str5 == str6);  \/\/ true\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-52\">\n<h3 class=\"wp-block-heading\" id=\"i-7\">2.3 \u8aa4\u3063\u305f\u6bd4\u8f03\u65b9\u6cd5\u306b\u3088\u308b\u6df1\u523b\u306a\u30d0\u30b0\u4e8b\u4f8b<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-53\">\n<p>\u6587\u5b57\u5217\u6bd4\u8f03\u3067<code>==<\/code>\u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u306b\u3088\u308b\u5178\u578b\u7684\u306a\u30d0\u30b0\u4e8b\u4f8b\u3092\u898b\u3066\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-54\">\n<p>\u30001. <strong>\u30e6\u30fc\u30b6\u30fc\u8a8d\u8a3c\u306e\u30d0\u30b0<\/strong><\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">public class LoginBug {\n    public static void main(String[] args) {\n        \/\/ \u30e6\u30fc\u30b6\u30fc\u5165\u529b\u3092\u6a21\u64ec\uff08\u5b9f\u969b\u306f\u30d5\u30a9\u30fc\u30e0\u306a\u3069\u304b\u3089\u53d6\u5f97\uff09\n        String userInput = new String(\"admin\");\n        String validPassword = \"admin\";\n\n        \/\/ \u5371\u967a\u306a\u6bd4\u8f03\u65b9\u6cd5\n        if (userInput == validPassword) {  \/\/ \u307b\u3068\u3093\u3069\u306e\u5834\u5408false\u306b\u306a\u308b\n            System.out.println(\"\u30ed\u30b0\u30a4\u30f3\u6210\u529f\");  \/\/ \u5b9f\u884c\u3055\u308c\u306a\u3044\n        }\n\n        \/\/ \u6b63\u3057\u3044\u6bd4\u8f03\u65b9\u6cd5\n        if (userInput.equals(validPassword)) {  \/\/ \u6b63\u3057\u304f\u6bd4\u8f03\u3055\u308c\u308b\n            System.out.println(\"\u30ed\u30b0\u30a4\u30f3\u6210\u529f\");  \/\/ \u5b9f\u884c\u3055\u308c\u308b\n        }\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-55\">\n<p>\u30002. <strong>\u8a2d\u5b9a\u5024\u306e\u5224\u5b9a\u30df\u30b9<\/strong><\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">public class ConfigurationBug {\n    public static void main(String[] args) {\n        \/\/ \u8a2d\u5b9a\u30d5\u30a1\u30a4\u30eb\u304b\u3089\u8aad\u307f\u8fbc\u3093\u3060\u5024\u3092\u60f3\u5b9a\n        String mode = new String(\"DEBUG\");\n\n        \/\/ \u5371\u967a\u306a\u6761\u4ef6\u5206\u5c90\n        if (mode == \"DEBUG\") {  \/\/ \u610f\u56f3\u3057\u305f\u901a\u308a\u306b\u52d5\u4f5c\u3057\u306a\u3044\n            enableDebugLogging();\n        }\n\n        \/\/ \u6b63\u3057\u3044\u6761\u4ef6\u5206\u5c90\n        if (\"DEBUG\".equals(mode)) {  \/\/ \u6b63\u3057\u304f\u52d5\u4f5c\u3059\u308b\n            enableDebugLogging();\n        }\n    }\n\n    private static void enableDebugLogging() {\n        System.out.println(\"\u30c7\u30d0\u30c3\u30b0\u30ed\u30b0\u3092\u6709\u52b9\u5316\u3057\u307e\u3057\u305f\");\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-59\">\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\">\u30d0\u30b0\u3092\u9632\u3050\u305f\u3081\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/div><div class=\"sgb-box-simple__body\" style=\"border-color:var(--wp--preset--color--sango-main);background-color:#FFF\">\n<ol class=\"wp-block-list\"><div id=\"sgb-css-id-56\">\n<li>\u6587\u5b57\u5217\u6bd4\u8f03\u306b\u306f\u5e38\u306b<code>equals()<\/code>\u3092\u4f7f\u7528\u3059\u308b<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-57\">\n<li><code>null<\/code>\u5b89\u5168\u306a\u6bd4\u8f03\u306e\u305f\u3081\u306b\u3001\u5b9a\u6570\u3092\u5de6\u8fba\u306b\u7f6e\u304f<\/li>\n<\/div>\n\n<div id=\"sgb-css-id-58\">\n<li>IDE\u8b66\u544a\u3092\u6d3b\u7528\u3057\u3001<code>==<\/code>\u306b\u3088\u308b\u6587\u5b57\u5217\u6bd4\u8f03\u3092\u691c\u51fa\u3059\u308b<\/li>\n<\/div>\n\n\n<li>\u30b3\u30fc\u30c9\u30ec\u30d3\u30e5\u30fc\u3067\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u65b9\u6cd5\u3092\u78ba\u8a8d\u3059\u308b<\/li>\n<\/ol>\n<\/div><\/div>\n<\/div>\n\n<div id=\"sgb-css-id-60\">\n<p>\u3053\u306e\u3088\u3046\u306a\u6ce8\u610f\u70b9\u3092\u610f\u8b58\u3059\u308b\u3053\u3068\u3067\u3001\u6587\u5b57\u5217\u6bd4\u8f03\u306b\u95a2\u9023\u3059\u308b\u30d0\u30b0\u3092\u672a\u7136\u306b\u9632\u3050\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-61\">\n<h2 class=\"wp-block-heading\" id=\"i-8\">\uff13\uff0e\u52b9\u7387\u7684\u306a\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u5b9f\u8df5\u30c6\u30af\u30cb\u30c3\u30af<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-62\">\n<h3 class=\"wp-block-heading\" id=\"i-9\">3.1 \u5927\u6587\u5b57\u5c0f\u6587\u5b57\u3092\u533a\u5225\u3057\u306a\u3044\u6bd4\u8f03\u65b9\u6cd5<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-63\">\n<p>\u5927\u6587\u5b57\u5c0f\u6587\u5b57\u3092\u533a\u5225\u3057\u306a\u3044\u6bd4\u8f03\u306f\u3001\u30e6\u30fc\u30b6\u30fc\u5165\u529b\u3084\u30b7\u30b9\u30c6\u30e0\u8a2d\u5b9a\u306e\u691c\u8a3c\u3067\u3088\u304f\u5fc5\u8981\u3068\u306a\u308a\u307e\u3059\u3002\u4ee5\u4e0b\u306b\u52b9\u7387\u7684\u306a\u5b9f\u88c5\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=\"\">public class CaseInsensitiveComparison {\n    public static void main(String[] args) {\n        String str1 = \"Hello World\";\n        String str2 = \"hello world\";\n\n        \/\/ \u65b9\u6cd51: equalsIgnoreCase()\u306e\u4f7f\u7528\uff08\u63a8\u5968\uff09\n        boolean result1 = str1.equalsIgnoreCase(str2);  \/\/ true\n\n        \/\/ \u65b9\u6cd52: toLowerCase()\u3092\u4f7f\u7528\uff08\u975e\u63a8\u5968\uff09\n        boolean result2 = str1.toLowerCase().equals(str2.toLowerCase());  \/\/ true\n\n        \/\/ \u65b9\u6cd53: Locale\u6307\u5b9a\u306b\u3088\u308b\u56fd\u969b\u5316\u5bfe\u5fdc\n        boolean result3 = str1.toLowerCase(Locale.ENGLISH)\n                             .equals(str2.toLowerCase(Locale.ENGLISH));  \/\/ true\n\n        \/\/ \u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6bd4\u8f03\u7528\u306e\u30d9\u30f3\u30c1\u30de\u30fc\u30af\n        String[] testStrings = new String[]{\"Hello\", \"HELLO\", \"hello\"};\n        for (String s : testStrings) {\n            long start = System.nanoTime();\n            for (int i = 0; i &lt; 1000000; i++) {\n                str1.equalsIgnoreCase(s);\n            }\n            long end = System.nanoTime();\n            System.out.printf(\"equalsIgnoreCase: %d ns%n\", (end - start) \/ 1000000);\n        }\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-64\">\n<h3 class=\"wp-block-heading\" id=\"i-10\">3.2 null\u30bb\u30fc\u30d5\u306a\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u5b9f\u88c5\u65b9\u6cd5<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-65\">\n<p><code>null<\/code>\u5024\u3092\u5b89\u5168\u306b\u6271\u3048\u308b\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u5b9f\u88c5\u306f\u3001\u5805\u7262\u306a\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u958b\u767a\u306b\u4e0d\u53ef\u6b20\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 NullSafeComparison {\n    public static void main(String[] args) {\n        String str1 = null;\n        String str2 = \"Hello\";\n\n        \/\/ \u65b9\u6cd51: Objects.equals()\u306e\u4f7f\u7528\uff08\u63a8\u5968\uff09\n        boolean result1 = Objects.equals(str1, str2);  \/\/ false\n\n        \/\/ \u65b9\u6cd52: \u5b9a\u6570\u6587\u5b57\u5217\u304b\u3089equals()\u3092\u547c\u3073\u51fa\u3059\n        boolean result2 = \"Hello\".equals(str1);  \/\/ false\n\n        \/\/ \u65b9\u6cd53: \u30ab\u30b9\u30bf\u30e0\u30e6\u30fc\u30c6\u30a3\u30ea\u30c6\u30a3\u30e1\u30bd\u30c3\u30c9\n        boolean result3 = isEqual(str1, str2);  \/\/ false\n    }\n\n    \/\/ null\u30bb\u30fc\u30d5\u306a\u6bd4\u8f03\u7528\u30e6\u30fc\u30c6\u30a3\u30ea\u30c6\u30a3\u30e1\u30bd\u30c3\u30c9\n    public static boolean isEqual(String str1, String str2) {\n        if (str1 == str2) return true;  \/\/ \u4e21\u65b9null\u307e\u305f\u306f\u540c\u3058\u53c2\u7167\n        if (str1 == null || str2 == null) return false;\n        return str1.equals(str2);\n    }\n\n    \/\/ \u5927\u6587\u5b57\u5c0f\u6587\u5b57\u3092\u533a\u5225\u3057\u306a\u3044null\u30bb\u30fc\u30d5\u306a\u6bd4\u8f03\n    public static boolean isEqualIgnoreCase(String str1, String str2) {\n        if (str1 == str2) return true;\n        if (str1 == null || str2 == null) return false;\n        return str1.equalsIgnoreCase(str2);\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-66\">\n<h3 class=\"wp-block-heading\" id=\"i-11\">3.3 \u8907\u6570\u306e\u6587\u5b57\u5217\u3092\u52b9\u7387\u7684\u306b\u6bd4\u8f03\u3059\u308b\u30c6\u30af\u30cb\u30c3\u30af<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-67\">\n<p>\u8907\u6570\u306e\u6587\u5b57\u5217\u3092\u6bd4\u8f03\u3059\u308b\u5834\u5408\u3001\u52b9\u7387\u7684\u306a\u30a2\u30d7\u30ed\u30fc\u30c1\u304c\u91cd\u8981\u3067\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">public class MultipleStringComparison {\n    public static void main(String[] args) {\n        List&lt;String&gt; validValues = Arrays.asList(\"apple\", \"banana\", \"orange\");\n        String target = \"banana\";\n\n        \/\/ \u65b9\u6cd51: Stream\u3092\u4f7f\u7528\u3057\u305f\u6bd4\u8f03\uff08Java 8+\uff09\n        boolean containsStream = validValues.stream()\n                                         .anyMatch(target::equals);\n\n        \/\/ \u65b9\u6cd52: HashSet\u3092\u4f7f\u7528\u3057\u305f\u9ad8\u901f\u306a\u691c\u7d22\n        Set&lt;String&gt; validSet = new HashSet&lt;&gt;(validValues);\n        boolean containsSet = validSet.contains(target);\n\n        \/\/ \u65b9\u6cd53: \u8907\u6570\u6761\u4ef6\u306eOR\u6bd4\u8f03\n        String value = \"test\";\n        boolean matchesAny = value.equals(\"test\") || \n                           value.equals(\"demo\") || \n                           value.equals(\"sample\");\n\n        \/\/ \u30d1\u30bf\u30fc\u30f3\u30de\u30c3\u30c1\u30f3\u30b0\u3092\u4f7f\u7528\u3057\u305f\u6bd4\u8f03\uff08Java 17+\uff09\n        String fruit = \"apple\";\n        boolean isValidFruit = switch (fruit) {\n            case \"apple\", \"banana\", \"orange\" -&gt; true;\n            default -&gt; false;\n        };\n    }\n\n    \/\/ \u30ab\u30b9\u30bf\u30e0\u6bd4\u8f03\u30e1\u30bd\u30c3\u30c9\uff1a\u8907\u6570\u306e\u6587\u5b57\u5217\u3068\u306e\u4e00\u81f4\u3092\u30c1\u30a7\u30c3\u30af\n    public static boolean matchesAny(String target, String... candidates) {\n        if (target == null) return false;\n        for (String candidate : candidates) {\n            if (target.equals(candidate)) return true;\n        }\n        return false;\n    }\n\n    \/\/ \u5927\u6587\u5b57\u5c0f\u6587\u5b57\u3092\u533a\u5225\u3057\u306a\u3044\u8907\u6570\u6587\u5b57\u5217\u6bd4\u8f03\n    public static boolean matchesAnyIgnoreCase(String target, String... candidates) {\n        if (target == null) return false;\n        for (String candidate : candidates) {\n            if (target.equalsIgnoreCase(candidate)) return true;\n        }\n        return false;\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-68\">\n<p><strong>\u6bd4\u8f03\u51e6\u7406\u306e\u52b9\u7387\u3092\u4e0a\u3052\u308b\u305f\u3081\u306e\u30dd\u30a4\u30f3\u30c8\uff1a<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-69\">\n<p>\u3000<strong>1. \u30c7\u30fc\u30bf\u69cb\u9020\u306e\u9078\u629e<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-70\">\n<p>\u3000\u3000\u25cf \u5c11\u6570\u306e\u6bd4\u8f03\uff1a\u76f4\u63a5\u7684\u306a<code>equals()<\/code><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-71\">\n<p>\u3000\u3000\u25cf \u5927\u91cf\u306e\u6bd4\u8f03\uff1a<code>HashSet<\/code>\u3092\u4f7f\u7528<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-72\">\n<p>\u3000<strong>2. \u30e1\u30e2\u30ea\u52b9\u7387<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-73\">\n<p>\u3000\u3000\u25cf \u4e2d\u9593\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u751f\u6210\u3092\u907f\u3051\u308b<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-74\">\n<p>\u3000\u3000\u25cf \u5fc5\u8981\u306a\u5834\u5408\u306e\u307f\u5927\u6587\u5b57\u5c0f\u6587\u5b57\u5909\u63db\u3092\u5b9f\u884c<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-75\">\n<p>\u3000<strong>3. \u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u8003\u616e\u4e8b\u9805<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-76\">\n<p>\u3000\u3000\u25cf \u30eb\u30fc\u30d7\u5185\u3067\u306e\u6587\u5b57\u5217\u6bd4\u8f03\u306f<code>String.intern()<\/code>\u306e\u4f7f\u7528\u3092\u691c\u8a0e<\/p>\n<\/div>\n\n\n<p>\u3000\u3000\u25cf \u983b\u7e41\u306a\u6bd4\u8f03\u306b\u306f\u4e8b\u524d\u306b\u30cf\u30c3\u30b7\u30e5\u5024\u3092\u8a08\u7b97<\/p>\n\n\n<div id=\"sgb-css-id-77\">\n<p>\u3053\u308c\u3089\u306e\u30c6\u30af\u30cb\u30c3\u30af\u3092\u9069\u5207\u306b\u7d44\u307f\u5408\u308f\u305b\u308b\u3053\u3068\u3067\u3001\u52b9\u7387\u7684\u3067\u4fdd\u5b88\u6027\u306e\u9ad8\u3044\u6587\u5b57\u5217\u6bd4\u8f03\u51e6\u7406\u3092\u5b9f\u73fe\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-78\">\n<h2 class=\"wp-block-heading\" id=\"i-12\">\uff14\uff0e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u8003\u616e\u3057\u305f\u6587\u5b57\u5217\u6bd4\u8f03<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-79\">\n<h3 class=\"wp-block-heading\" id=\"i-13\">4.1 String.intern()\u30e1\u30bd\u30c3\u30c9\u3092\u6d3b\u7528\u3057\u305f\u6700\u9069\u5316<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-80\">\n<p><code>String.intern()<\/code>\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u6587\u5b57\u5217\u30d7\u30fc\u30eb\u3092\u6d3b\u7528\u3057\u3066\u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u3092\u524a\u6e1b\u3057\u3001\u6bd4\u8f03\u51e6\u7406\u3092\u9ad8\u901f\u5316\u3059\u308b\u5f37\u529b\u306a\u6a5f\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=\"\">public class StringInternExample {\n    public static void main(String[] args) {\n        \/\/ intern()\u306e\u57fa\u672c\u7684\u306a\u4f7f\u7528\u4f8b\n        String str1 = new String(\"Hello\").intern();\n        String str2 = \"Hello\";\n        System.out.println(str1 == str2);  \/\/ true\uff08\u540c\u3058\u53c2\u7167\u3092\u6307\u3059\uff09\n\n        \/\/ \u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6bd4\u8f03\n        benchmark();\n    }\n\n    private static void benchmark() {\n        \/\/ \u30c6\u30b9\u30c8\u30c7\u30fc\u30bf\u306e\u6e96\u5099\n        List&lt;String&gt; testData = new ArrayList&lt;&gt;();\n        for (int i = 0; i &lt; 1000; i++) {\n            testData.add(new String(\"Test\" + (i % 10)));  \/\/ \u610f\u56f3\u7684\u306b\u91cd\u8907\u3092\u4f5c\u6210\n        }\n\n        \/\/ intern()\u3092\u4f7f\u7528\u3057\u306a\u3044\u5834\u5408\n        long startWithoutIntern = System.nanoTime();\n        for (int i = 0; i &lt; testData.size(); i++) {\n            for (int j = i + 1; j &lt; testData.size(); j++) {\n                testData.get(i).equals(testData.get(j));\n            }\n        }\n        long timeWithoutIntern = System.nanoTime() - startWithoutIntern;\n\n        \/\/ intern()\u3092\u4f7f\u7528\u3059\u308b\u5834\u5408\n        List&lt;String&gt; internedData = testData.stream()\n            .map(String::intern)\n            .collect(Collectors.toList());\n\n        long startWithIntern = System.nanoTime();\n        for (int i = 0; i &lt; internedData.size(); i++) {\n            for (int j = i + 1; j &lt; internedData.size(); j++) {\n                internedData.get(i) == internedData.get(j);  \/\/ ==\u306b\u3088\u308b\u6bd4\u8f03\u304c\u53ef\u80fd\n            }\n        }\n        long timeWithIntern = System.nanoTime() - startWithIntern;\n\n        System.out.printf(\"Without intern: %d ns%n\", timeWithoutIntern);\n        System.out.printf(\"With intern: %d ns%n\", timeWithIntern);\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-81\">\n<h3 class=\"wp-block-heading\" id=\"i-14\">4.2 \u5927\u91cf\u306e\u6587\u5b57\u5217\u6bd4\u8f03\u6642\u306e\u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u306e\u524a\u6e1b\u65b9\u6cd5<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-82\">\n<p>\u5927\u91cf\u306e\u6587\u5b57\u5217\u3092\u52b9\u7387\u7684\u306b\u6bd4\u8f03\u3059\u308b\u969b\u306e\u30e1\u30e2\u30ea\u6700\u9069\u5316\u30c6\u30af\u30cb\u30c3\u30af\u306f\u4ee5\u4e0b\u306e\u901a\u308a\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 MemoryEfficientComparison {\n    public static void main(String[] args) {\n        \/\/ \u30e1\u30e2\u30ea\u52b9\u7387\u306e\u826f\u3044\u6587\u5b57\u5217\u30bb\u30c3\u30c8\u306e\u5b9f\u88c5\n        Set&lt;String&gt; efficientSet = Collections.newSetFromMap(\n            new WeakHashMap&lt;String, Boolean&gt;());\n\n        \/\/ \u30ab\u30b9\u30bf\u30e0\u30ad\u30e3\u30c3\u30b7\u30e5\u306e\u5b9f\u88c5\n        class StringCache {\n            private final WeakHashMap&lt;String, WeakReference&lt;String&gt;&gt; cache = \n                new WeakHashMap&lt;&gt;();\n\n            public String intern(String str) {\n                WeakReference&lt;String&gt; cached = cache.get(str);\n                if (cached != null) {\n                    String cachedStr = cached.get();\n                    if (cachedStr != null) return cachedStr;\n                }\n                cache.put(str, new WeakReference&lt;&gt;(str));\n                return str;\n            }\n        }\n\n        StringCache cache = new StringCache();\n\n        \/\/ \u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u306e\u6bd4\u8f03\n        demonstrateMemoryUsage();\n    }\n\n    private static void demonstrateMemoryUsage() {\n        Runtime runtime = Runtime.getRuntime();\n\n        \/\/ \u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u3092\u6e2c\u5b9a\u3059\u308b\u88dc\u52a9\u30e1\u30bd\u30c3\u30c9\n        long getMemoryUsage() {\n            runtime.gc();  \/\/ GC\u3092\u4fc3\u3059\n            return runtime.totalMemory() - runtime.freeMemory();\n        }\n\n        long beforeMemory = getMemoryUsage();\n\n        \/\/ \u901a\u5e38\u306e\u6587\u5b57\u5217\u51e6\u7406\n        List&lt;String&gt; normalStrings = new ArrayList&lt;&gt;();\n        for (int i = 0; i &lt; 100000; i++) {\n            normalStrings.add(new String(\"Test\" + (i % 100)));\n        }\n\n        long afterNormalMemory = getMemoryUsage();\n\n        \/\/ intern()\u3092\u4f7f\u7528\u3057\u305f\u51e6\u7406\n        List&lt;String&gt; internedStrings = new ArrayList&lt;&gt;();\n        for (int i = 0; i &lt; 100000; i++) {\n            internedStrings.add((\"Test\" + (i % 100)).intern());\n        }\n\n        long afterInternedMemory = getMemoryUsage();\n\n        System.out.printf(\"Normal strings memory: %d bytes%n\", \n            afterNormalMemory - beforeMemory);\n        System.out.printf(\"Interned strings memory: %d bytes%n\", \n            afterInternedMemory - afterNormalMemory);\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-83\">\n<h3 class=\"wp-block-heading\" id=\"i-15\">4.3 \u6587\u5b57\u5217\u6bd4\u8f03\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u8a08\u6e2c\u3068\u6539\u5584<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-84\">\n<p>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u6b63\u78ba\u306b\u8a08\u6e2c\u3057\u3001\u6539\u5584\u3059\u308b\u65b9\u6cd5\u306f\u4ee5\u4e0b\u306e\u901a\u308a\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 StringComparisonBenchmark {\n    private static final int ITERATION_COUNT = 1_000_000;\n\n    public static void main(String[] args) {\n        \/\/ \u30c6\u30b9\u30c8\u30c7\u30fc\u30bf\u306e\u6e96\u5099\n        String str1 = \"Hello, World!\";\n        String str2 = new String(\"Hello, World!\");\n        String str3 = str2.intern();\n\n        \/\/ \u5404\u6bd4\u8f03\u65b9\u6cd5\u306e\u30d9\u30f3\u30c1\u30de\u30fc\u30af\n        benchmarkEquals(str1, str2);\n        benchmarkEqualsIgnoreCase(str1, str2);\n        benchmarkCompareTo(str1, str2);\n        benchmarkReferenceComparison(str1, str3);\n\n        \/\/ JMH\u30b9\u30bf\u30a4\u30eb\u306e\u30de\u30a4\u30af\u30ed\u30d9\u30f3\u30c1\u30de\u30fc\u30af\n        runDetailedBenchmark();\n    }\n\n    private static void benchmarkEquals(String s1, String s2) {\n        long start = System.nanoTime();\n        for (int i = 0; i &lt; ITERATION_COUNT; i++) {\n            s1.equals(s2);\n        }\n        long end = System.nanoTime();\n        System.out.printf(\"equals(): %d ns\/op%n\", (end - start) \/ ITERATION_COUNT);\n    }\n\n    private static void benchmarkEqualsIgnoreCase(String s1, String s2) {\n        long start = System.nanoTime();\n        for (int i = 0; i &lt; ITERATION_COUNT; i++) {\n            s1.equalsIgnoreCase(s2);\n        }\n        long end = System.nanoTime();\n        System.out.printf(\"equalsIgnoreCase(): %d ns\/op%n\", \n            (end - start) \/ ITERATION_COUNT);\n    }\n\n    private static void benchmarkCompareTo(String s1, String s2) {\n        long start = System.nanoTime();\n        for (int i = 0; i &lt; ITERATION_COUNT; i++) {\n            s1.compareTo(s2);\n        }\n        long end = System.nanoTime();\n        System.out.printf(\"compareTo(): %d ns\/op%n\", \n            (end - start) \/ ITERATION_COUNT);\n    }\n\n    private static void benchmarkReferenceComparison(String s1, String s2) {\n        long start = System.nanoTime();\n        for (int i = 0; i &lt; ITERATION_COUNT; i++) {\n            boolean result = s1 == s2;\n        }\n        long end = System.nanoTime();\n        System.out.printf(\"== comparison: %d ns\/op%n\", \n            (end - start) \/ ITERATION_COUNT);\n    }\n\n    private static void runDetailedBenchmark() {\n        \/\/ \u30a6\u30a9\u30fc\u30e0\u30a2\u30c3\u30d7\n        for (int i = 0; i &lt; 100000; i++) {\n            String.valueOf(i).equals(String.valueOf(i));\n        }\n\n        \/\/ \u5b9f\u969b\u306e\u30d9\u30f3\u30c1\u30de\u30fc\u30af\uff08\u8907\u6570\u56de\u306e\u5b9f\u884c\u306e\u5e73\u5747\u3092\u53d6\u308b\uff09\n        List&lt;Long&gt; times = new ArrayList&lt;&gt;();\n        for (int i = 0; i &lt; 10; i++) {\n            long start = System.nanoTime();\n            for (int j = 0; j &lt; ITERATION_COUNT; j++) {\n                String.valueOf(j).equals(String.valueOf(j));\n            }\n            times.add(System.nanoTime() - start);\n        }\n\n        \/\/ \u7d71\u8a08\u306e\u8a08\u7b97\n        double average = times.stream()\n            .mapToLong(Long::longValue)\n            .average()\n            .orElse(0.0);\n\n        System.out.printf(\"Average time: %.2f ns\/op%n\", \n            average \/ ITERATION_COUNT);\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-85\">\n<p><strong>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316\u306e\u30dd\u30a4\u30f3\u30c8\uff1a<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-86\">\n<p>\u3000<strong>1. \u6587\u5b57\u5217\u30d7\u30fc\u30eb\u306e\u6d3b\u7528<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-87\">\n<p>\u3000\u3000\u25cf \u983b\u7e41\u306b\u4f7f\u7528\u3055\u308c\u308b\u6587\u5b57\u5217\u306b\u306f<code>intern()<\/code>\u3092\u4f7f\u7528<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-88\">\n<p>\u3000\u3000\u25cf \u30e1\u30e2\u30ea\u3068\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u306e\u30c8\u30ec\u30fc\u30c9\u30aa\u30d5\u3092\u8003\u616e<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-89\">\n<p>\u3000<strong>2. \u6bd4\u8f03\u30e1\u30bd\u30c3\u30c9\u306e\u9078\u629e<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-90\">\n<p>\u3000\u3000\u25cf \u5358\u7d14\u306a\u7b49\u4fa1\u6bd4\u8f03\u306b\u306f<code>equals()<\/code><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-91\">\n<p>\u3000\u3000\u25cf \u5927\u6587\u5b57\u5c0f\u6587\u5b57\u3092\u533a\u5225\u3057\u306a\u3044\u6bd4\u8f03\u306b\u306f<code>equalsIgnoreCase()<\/code><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-92\">\n<p>\u3000\u3000\u25cf \u9806\u5e8f\u6bd4\u8f03\u306b\u306f<code>compareTo()<\/code><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-93\">\n<p>\u3000<strong>3. \u30e1\u30e2\u30ea\u7ba1\u7406\u306e\u6700\u9069\u5316<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-94\">\n<p>\u3000\u3000\u25cf <code>WeakHashMap<\/code>\u306b\u3088\u308b\u81ea\u52d5\u30e1\u30e2\u30ea\u89e3\u653e<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-95\">\n<p>\u3000\u3000\u25cf \u6587\u5b57\u5217\u30ad\u30e3\u30c3\u30b7\u30e5\u306e\u9069\u5207\u306a\u5b9f\u88c5<\/p>\n<\/div>\n\n\n<p>\u3000\u3000\u25cf GC\u3078\u306e\u5f71\u97ff\u3092\u8003\u616e<\/p>\n\n\n<div id=\"sgb-css-id-96\">\n<p>\u3053\u308c\u3089\u306e\u6700\u9069\u5316\u30c6\u30af\u30cb\u30c3\u30af\u3092\u9069\u5207\u306b\u7d44\u307f\u5408\u308f\u305b\u308b\u3053\u3068\u3067\u3001\u52b9\u7387\u7684\u306a\u6587\u5b57\u5217\u6bd4\u8f03\u51e6\u7406\u3092\u5b9f\u73fe\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-97\">\n<h2 class=\"wp-block-heading\" id=\"i-16\">\uff15\uff0e\u5b9f\u8df5\u7684\u306a\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-98\">\n<h3 class=\"wp-block-heading\" id=\"i-17\">5.1 \u53ef\u8aad\u6027\u306e\u9ad8\u3044\u6587\u5b57\u5217\u6bd4\u8f03\u30b3\u30fc\u30c9\u306e\u66f8\u304d\u65b9<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-99\">\n<p>\u53ef\u8aad\u6027\u306e\u9ad8\u3044\u30b3\u30fc\u30c9\u306f\u4fdd\u5b88\u6027\u3092\u9ad8\u3081\u3001\u30d0\u30b0\u3092\u9632\u3050\u91cd\u8981\u306a\u8981\u7d20\u3067\u3059\u3002\u4ee5\u4e0b\u306b\u3001\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\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 ReadableStringComparison {\n    \/\/ \u5b9a\u6570\u306e\u9069\u5207\u306a\u5b9a\u7fa9\n    private static final String STATUS_ACTIVE = \"ACTIVE\";\n    private static final String STATUS_INACTIVE = \"INACTIVE\";\n\n    public static void main(String[] args) {\n        \/\/ \u826f\u3044\u4f8b\uff1a\u5b9a\u6570\u3092\u4f7f\u7528\u3057\u305f\u6bd4\u8f03\n        String status = getStatus();\n        if (STATUS_ACTIVE.equals(status)) {\n            processActiveStatus();\n        }\n\n        \/\/ \u826f\u3044\u4f8b\uff1anull\u5b89\u5168\u306a\u6bd4\u8f03\u3092\u30e6\u30fc\u30c6\u30a3\u30ea\u30c6\u30a3\u30e1\u30bd\u30c3\u30c9\u306b\u30ab\u30d7\u30bb\u30eb\u5316\n        if (StringUtils.isEqual(getUserInput(), \"expected\")) {\n            processValidInput();\n        }\n\n        \/\/ \u826f\u3044\u4f8b\uff1a\u8907\u6570\u306e\u6761\u4ef6\u3092\u30e1\u30bd\u30c3\u30c9\u306b\u62bd\u51fa\n        if (isValidStatus(status)) {\n            processValidStatus();\n        }\n    }\n\n    \/\/ \u30e6\u30fc\u30c6\u30a3\u30ea\u30c6\u30a3\u30af\u30e9\u30b9\u306e\u5b9f\u88c5\u4f8b\n    public static class StringUtils {\n        private StringUtils() {} \/\/ \u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u5316\u9632\u6b62\n\n        public static boolean isEqual(String str1, String str2) {\n            return Objects.equals(str1, str2);\n        }\n\n        public static boolean isEqualIgnoreCase(String str1, String str2) {\n            if (str1 == str2) return true;\n            if (str1 == null || str2 == null) return false;\n            return str1.equalsIgnoreCase(str2);\n        }\n\n        public static boolean containsIgnoreCase(String text, String searchStr) {\n            if (text == null || searchStr == null) return false;\n            return text.toLowerCase().contains(searchStr.toLowerCase());\n        }\n    }\n\n    \/\/ \u8907\u96d1\u306a\u6761\u4ef6\u3092\u30e1\u30bd\u30c3\u30c9\u306b\u62bd\u51fa\n    private static boolean isValidStatus(String status) {\n        return STATUS_ACTIVE.equals(status) || \n               STATUS_INACTIVE.equals(status);\n    }\n\n    \/\/ \u30b5\u30f3\u30d7\u30eb\u30e1\u30bd\u30c3\u30c9\n    private static String getStatus() { return STATUS_ACTIVE; }\n    private static void processActiveStatus() {}\n    private static void processValidInput() {}\n    private static void processValidStatus() {}\n    private static String getUserInput() { return \"expected\"; }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-100\">\n<h3 class=\"wp-block-heading\" id=\"i-18\">5.2 \u30e6\u30cb\u30c3\u30c8\u30c6\u30b9\u30c8\u3067\u306e\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u691c\u8a3c\u65b9\u6cd5<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-101\">\n<p>\u52b9\u679c\u7684\u306a\u30e6\u30cb\u30c3\u30c8\u30c6\u30b9\u30c8\u306f\u3001\u6587\u5b57\u5217\u6bd4\u8f03\u30ed\u30b8\u30c3\u30af\u306e\u4fe1\u983c\u6027\u3092\u78ba\u4fdd\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=\"\">import org.junit.jupiter.api.Test;\nimport org.junit.jupiter.api.DisplayName;\nimport static org.junit.jupiter.api.Assertions.*;\n\npublic class StringComparisonTest {\n    @Test\n    @DisplayName(\"\u57fa\u672c\u7684\u306a\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u30c6\u30b9\u30c8\")\n    void testBasicStringComparison() {\n        String str1 = \"Hello\";\n        String str2 = \"Hello\";\n        String str3 = new String(\"Hello\");\n\n        \/\/ \u7b49\u4fa1\u6027\u306e\u30c6\u30b9\u30c8\n        assertTrue(str1.equals(str2), \"\u540c\u3058\u30ea\u30c6\u30e9\u30eb\u306f\u7b49\u4fa1\u3067\u3042\u308b\u3079\u304d\");\n        assertTrue(str1.equals(str3), \"\u5185\u5bb9\u304c\u540c\u3058\u6587\u5b57\u5217\u306f\u7b49\u4fa1\u3067\u3042\u308b\u3079\u304d\");\n\n        \/\/ \u53c2\u7167\u6bd4\u8f03\u306e\u30c6\u30b9\u30c8\n        assertSame(str1, str2, \"\u540c\u3058\u30ea\u30c6\u30e9\u30eb\u306f\u540c\u3058\u53c2\u7167\u3067\u3042\u308b\u3079\u304d\");\n        assertNotSame(str1, str3, \"new \u3067\u4f5c\u6210\u3057\u305f\u6587\u5b57\u5217\u306f\u7570\u306a\u308b\u53c2\u7167\u3067\u3042\u308b\u3079\u304d\");\n    }\n\n    @Test\n    @DisplayName(\"null\u5b89\u5168\u306a\u6bd4\u8f03\u306e\u30c6\u30b9\u30c8\")\n    void testNullSafeComparison() {\n        String nullString = null;\n        String emptyString = \"\";\n        String normalString = \"test\";\n\n        \/\/ null\u30b1\u30fc\u30b9\u306e\u30c6\u30b9\u30c8\n        assertFalse(StringUtils.isEqual(nullString, normalString));\n        assertFalse(StringUtils.isEqual(normalString, nullString));\n        assertTrue(StringUtils.isEqual(nullString, nullString));\n\n        \/\/ \u7a7a\u6587\u5b57\u5217\u306e\u30c6\u30b9\u30c8\n        assertFalse(StringUtils.isEqual(emptyString, nullString));\n        assertTrue(StringUtils.isEqual(emptyString, emptyString));\n    }\n\n    @Test\n    @DisplayName(\"\u5927\u6587\u5b57\u5c0f\u6587\u5b57\u3092\u533a\u5225\u3057\u306a\u3044\u6bd4\u8f03\u306e\u30c6\u30b9\u30c8\")\n    void testCaseInsensitiveComparison() {\n        String upper = \"HELLO\";\n        String lower = \"hello\";\n        String mixed = \"Hello\";\n\n        assertTrue(upper.equalsIgnoreCase(lower));\n        assertTrue(mixed.equalsIgnoreCase(lower));\n        assertTrue(upper.equalsIgnoreCase(mixed));\n    }\n\n    @Test\n    @DisplayName(\"\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u8981\u4ef6\u306e\u30c6\u30b9\u30c8\")\n    void testPerformance() {\n        String testStr = \"Performance Test String\";\n        long startTime = System.nanoTime();\n\n        \/\/ 1000\u56de\u306e\u6bd4\u8f03\u3092\u5b9f\u884c\n        for (int i = 0; i &lt; 1000; i++) {\n            testStr.equals(\"Performance Test String\");\n        }\n\n        long duration = System.nanoTime() - startTime;\n        assertTrue(duration &lt; 1_000_000, \"\u6bd4\u8f03\u306f1\u30df\u30ea\u79d2\u4ee5\u5185\u306b\u5b8c\u4e86\u3059\u3079\u304d\");\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-102\">\n<h3 class=\"wp-block-heading\" id=\"i-19\">5.3 \u30bb\u30ad\u30e5\u30ea\u30c6\u30a3\u3092\u8003\u616e\u3057\u305f\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u5b9f\u88c5<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-103\">\n<p>\u30bb\u30ad\u30e5\u30ea\u30c6\u30a3\u3092\u8003\u616e\u3057\u305f\u6587\u5b57\u5217\u6bd4\u8f03\u306f\u3001\u7279\u306b\u8a8d\u8a3c\u3084\u30d1\u30b9\u30ef\u30fc\u30c9\u691c\u8a3c\u3067\u91cd\u8981\u3067\u3059\u3002<\/p>\n<\/div>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">public class SecureStringComparison {\n    public static void main(String[] args) {\n        \/\/ \u30bb\u30ad\u30e5\u30a2\u306a\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u4f8b\n        demonstrateSecureComparison();\n    }\n\n    public static class SecureStringUtils {\n        \/\/ \u30bf\u30a4\u30df\u30f3\u30b0\u653b\u6483\u3092\u9632\u3050\u305f\u3081\u306e\u5b9a\u6570\u6642\u9593\u6bd4\u8f03\n        public static boolean constantTimeEquals(String a, String b) {\n            if (a == null || b == null) {\n                return a == b;\n            }\n\n            byte[] aBytes = a.getBytes(StandardCharsets.UTF_8);\n            byte[] bBytes = b.getBytes(StandardCharsets.UTF_8);\n\n            return MessageDigest.isEqual(aBytes, bBytes);\n        }\n\n        \/\/ \u30d1\u30b9\u30ef\u30fc\u30c9\u6bd4\u8f03\u7528\u306e\u30bb\u30ad\u30e5\u30a2\u306a\u5b9f\u88c5\n        public static boolean verifyPassword(String inputPassword, \n                                          String storedHash) {\n            try {\n                \/\/ BCrypt\u3092\u4f7f\u7528\u3057\u305f\u30cf\u30c3\u30b7\u30e5\u6bd4\u8f03\n                return BCrypt.checkpw(inputPassword, storedHash);\n            } catch (IllegalArgumentException e) {\n                \/\/ \u30ed\u30b0\u51fa\u529b\uff08\u672c\u756a\u74b0\u5883\u3067\u306f\u9069\u5207\u306a\u30ed\u30b0\u51e6\u7406\u3092\u5b9f\u88c5\uff09\n                System.err.println(\"Invalid hash format\");\n                return false;\n            }\n        }\n    }\n\n    private static void demonstrateSecureComparison() {\n        \/\/ \u30bb\u30ad\u30e5\u30ea\u30c6\u30a3\u4e0a\u91cd\u8981\u306a\u6587\u5b57\u5217\u306e\u6bd4\u8f03\n        String userToken = \"user-secret-token\";\n        String validToken = \"user-secret-token\";\n\n        \/\/ \u826f\u3044\u4f8b\uff1a\u5b9a\u6570\u6642\u9593\u3067\u306e\u6bd4\u8f03\n        boolean isValidToken = SecureStringUtils\n            .constantTimeEquals(userToken, validToken);\n\n        \/\/ \u30d1\u30b9\u30ef\u30fc\u30c9\u306e\u691c\u8a3c\u4f8b\n        String inputPassword = \"user-password\";\n        String storedHash = BCrypt.hashpw(inputPassword, BCrypt.gensalt());\n\n        boolean isValidPassword = SecureStringUtils\n            .verifyPassword(inputPassword, storedHash);\n    }\n\n    \/\/ \u30bb\u30ad\u30e5\u30a2\u306a\u6587\u5b57\u5217\u51e6\u7406\u306e\u305f\u3081\u306e\u30e6\u30fc\u30c6\u30a3\u30ea\u30c6\u30a3\n    public static class SecureStringProcessor {\n        private static final int MAX_LENGTH = 1000; \/\/ \u9069\u5207\u306a\u4e0a\u9650\u5024\n\n        public static String sanitizeInput(String input) {\n            if (input == null) return null;\n\n            \/\/ \u9577\u3055\u306e\u5236\u9650\n            if (input.length() &gt; MAX_LENGTH) {\n                input = input.substring(0, MAX_LENGTH);\n            }\n\n            \/\/ \u7279\u6b8a\u6587\u5b57\u306e\u30a8\u30b9\u30b1\u30fc\u30d7\u51e6\u7406\n            return escapeSpecialCharacters(input);\n        }\n\n        private static String escapeSpecialCharacters(String input) {\n            return input.replaceAll(\"[&lt;&gt;&amp;\\\"']\", \"_\");\n        }\n    }\n}<\/pre>\n\n\n<div id=\"sgb-css-id-104\">\n<p><strong>\u30bb\u30ad\u30e5\u30a2\u306a\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u91cd\u8981\u306a\u30dd\u30a4\u30f3\u30c8\uff1a<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-105\">\n<p>\u3000<strong>1. \u30bf\u30a4\u30df\u30f3\u30b0\u653b\u6483\u3078\u306e\u5bfe\u7b56<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-106\">\n<p>\u3000\u3000\u25cf \u5b9a\u6570\u6642\u9593\u3067\u306e\u6bd4\u8f03\u3092\u5b9f\u88c5<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-107\">\n<p>\u3000\u3000\u25cf <code>MessageDigest.isEqual()<\/code>\u306e\u4f7f\u7528<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-108\">\n<p>\u3000<strong>2. \u30d1\u30b9\u30ef\u30fc\u30c9\u6bd4\u8f03\u306e\u5b89\u5168\u6027<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-109\">\n<p>\u3000\u3000\u25cf \u30cf\u30c3\u30b7\u30e5\u5316\u3055\u308c\u305f\u30d1\u30b9\u30ef\u30fc\u30c9\u306e\u4f7f\u7528<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-110\">\n<p>\u3000\u3000\u25cf \u9069\u5207\u306a\u30cf\u30c3\u30b7\u30e5\u30a2\u30eb\u30b4\u30ea\u30ba\u30e0\u306e\u9078\u629e<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-111\">\n<p>\u3000<strong>3. \u5165\u529b\u691c\u8a3c\u3068\u30b5\u30cb\u30bf\u30a4\u30ba<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-112\">\n<p>\u3000\u3000\u25cf \u9577\u3055\u306e\u5236\u9650<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-113\">\n<p>\u3000\u3000\u25cf \u7279\u6b8a\u6587\u5b57\u306e\u30a8\u30b9\u30b1\u30fc\u30d7<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-114\">\n<p>\u3000\u3000\u25cf NULL\u5024\u306e\u9069\u5207\u306a\u51e6\u7406<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-115\">\n<p>\u3000<strong>4. \u30a8\u30e9\u30fc\u51e6\u7406\u3068\u30ed\u30b0\u8a18\u9332<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-116\">\n<p>\u3000\u3000\u25cf \u4f8b\u5916\u306e\u9069\u5207\u306a\u51e6\u7406<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-117\">\n<p>\u3000\u3000\u25cf \u30bb\u30ad\u30e5\u30ea\u30c6\u30a3\u95a2\u9023\u306e\u30ed\u30b0\u8a18\u9332<\/p>\n<\/div>\n\n\n<p>\u3000\u3000\u25cf \u6a5f\u5bc6\u60c5\u5831\u306e\u4fdd\u8b77<\/p>\n\n\n<div id=\"sgb-css-id-118\">\n<p>\u3053\u308c\u3089\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\u3092\u9069\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u5b89\u5168\u3067\u4fdd\u5b88\u6027\u306e\u9ad8\u3044\u6587\u5b57\u5217\u6bd4\u8f03\u51e6\u7406\u3092\u5b9f\u88c5\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-119\">\n<h2 class=\"wp-block-heading\" id=\"i-20\">\u307e\u3068\u3081\uff1a\u52b9\u679c\u7684\u306a\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u5b9f\u8df5\u30ac\u30a4\u30c9<\/h2>\n<\/div>\n\n<div id=\"sgb-css-id-120\">\n<h3 class=\"wp-block-heading\" id=\"i-21\">\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u9078\u629e\u30d5\u30ed\u30fc\u30c1\u30e3\u30fc\u30c8<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-121\">\n<p>\u4ee5\u4e0b\u306e\u30d5\u30ed\u30fc\u30c1\u30e3\u30fc\u30c8\u3092\u53c2\u8003\u306b\u3001\u72b6\u6cc1\u306b\u5fdc\u3058\u305f\u9069\u5207\u306a\u6bd4\u8f03\u65b9\u6cd5\u3092\u9078\u629e\u3067\u304d\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-122\">\n<p>\u3000<strong>1. \u57fa\u672c\u7684\u306a\u7b49\u4fa1\u6027\u6bd4\u8f03\u304c\u5fc5\u8981\u306a\u5834\u5408<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-123\">\n<p>\u3000\u3000\u25cf \u27a1\ufe0f <code>equals()<\/code>\u3092\u4f7f\u7528<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-124\">\n<p>\u3000\u3000\u3000\u3000\u4f8b\uff1a<code>string1.equals(string2)<\/code><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-125\">\n<p>\u3000<strong>2. NULL\u5024\u306e\u53ef\u80fd\u6027\u304c\u3042\u308b\u5834\u5408<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-126\">\n<p>\u3000\u3000\u25cf \u27a1\ufe0f <code>Objects.equals()<\/code>\u307e\u305f\u306f\u5b9a\u6570\u3068\u306e\u6bd4\u8f03<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-127\">\n<p>\u3000\u3000\u3000\u3000\u4f8b\uff1a<code>Objects.equals(string1, string2)<\/code>\u307e\u305f\u306f<code>\"constant\".equals(string1)<\/code><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-128\">\n<p>\u3000<strong>3. \u5927\u6587\u5b57\u5c0f\u6587\u5b57\u3092\u533a\u5225\u3057\u306a\u3044\u6bd4\u8f03\u304c\u5fc5\u8981\u306a\u5834\u5408<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-129\">\n<p>\u3000\u3000\u25cf \u27a1\ufe0f <code>equalsIgnoreCase()<\/code>\u3092\u4f7f\u7528<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-130\">\n<p>\u3000\u3000\u3000\u3000\u4f8b\uff1a<code>string1.equalsIgnoreCase(string2)<\/code><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-131\">\n<p>\u3000<strong>4. \u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u304c\u91cd\u8981\u306a\u5834\u5408<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-132\">\n<p>\u3000\u3000\u25cf \u27a1\ufe0f <code>String.intern()<\/code>\u306e\u4f7f\u7528\u3092\u691c\u8a0e<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-133\">\n<p>\u3000\u3000\u3000\u3000\u4f8b\uff1a<code>string1.intern() == string2.intern()<\/code><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-134\">\n<p>\u3000<strong>5. \u30bb\u30ad\u30e5\u30ea\u30c6\u30a3\u304c\u91cd\u8981\u306a\u5834\u5408<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-135\">\n<p>\u3000\u3000\u25cf \u27a1\ufe0f \u5b9a\u6570\u6642\u9593\u6bd4\u8f03\u3092\u5b9f\u88c5<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-136\">\n<p>\u3000\u3000\u3000\u3000\u4f8b\uff1a<code>MessageDigest.isEqual(str1.getBytes(), str2.getBytes())<\/code><\/p>\n<\/div>\n\n\n<h3 class=\"wp-block-heading\" id=\"i-22\">\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\u30c1\u30a7\u30c3\u30af\u30ea\u30b9\u30c8<\/h3>\n\n\n<div id=\"sgb-css-id-137\">\n<p>\u2705 <strong>\u6587\u5b57\u5217\u6bd4\u8f03\u6642\u306e\u57fa\u672c\u30eb\u30fc\u30eb\uff1a<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-138\">\n<p>\u3000\u3000\u25cf \u5e38\u306b<code>equals()<\/code>\u3092\u4f7f\u7528\u3057\u3001<code>==<\/code>\u306f\u907f\u3051\u308b<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-139\">\n<p>\u3000\u3000\u25cf NULL\u5b89\u5168\u306a\u6bd4\u8f03\u3092\u5b9f\u88c5\u3059\u308b<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-140\">\n<p>\u3000\u3000\u25cf \u9069\u5207\u306a\u4f8b\u5916\u51e6\u7406\u3092\u884c\u3046<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-141\">\n<p>\u2705 <strong>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316\uff1a<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-142\">\n<p>\u3000\u3000\u25cf \u983b\u7e41\u306a\u6bd4\u8f03\u306b\u306f<code>String.intern()<\/code>\u3092\u691c\u8a0e<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-143\">\n<p>\u3000\u3000\u25cf \u5927\u91cf\u30c7\u30fc\u30bf\u51e6\u7406\u6642\u306f\u30ad\u30e3\u30c3\u30b7\u30e5\u3092\u6d3b\u7528<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-144\">\n<p>\u3000\u3000\u25cf \u4e0d\u5fc5\u8981\u306a\u6587\u5b57\u5217\u751f\u6210\u3092\u907f\u3051\u308b<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-145\">\n<p>\u2705 <strong>\u30bb\u30ad\u30e5\u30ea\u30c6\u30a3\u8003\u616e\u4e8b\u9805\uff1a<\/strong><\/p>\n<\/div>\n\n<div id=\"sgb-css-id-146\">\n<p>\u3000\u3000\u25cf \u6a5f\u5bc6\u60c5\u5831\u306e\u6bd4\u8f03\u306f\u5b9a\u6570\u6642\u9593\u3067\u884c\u3046<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-147\">\n<p>\u3000\u3000\u25cf \u5165\u529b\u5024\u306e\u9069\u5207\u306a\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u3092\u5b9f\u65bd<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-148\">\n<p>\u3000\u3000\u25cf \u30bb\u30ad\u30e5\u30a2\u306a\u6587\u5b57\u5217\u51e6\u7406\u30e9\u30a4\u30d6\u30e9\u30ea\u3092\u4f7f\u7528<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-149\">\n<h3 class=\"wp-block-heading\" id=\"i-23\">\u6b21\u306e\u30b9\u30c6\u30c3\u30d7<\/h3>\n<\/div>\n\n<div id=\"sgb-css-id-150\">\n<p>\u3053\u306e\u8a18\u4e8b\u3067\u5b66\u3093\u3060\u5185\u5bb9\u3092\u5b9f\u8df5\u3059\u308b\u305f\u3081\u306b\u3001\u4ee5\u4e0b\u306e\u30a2\u30af\u30b7\u30e7\u30f3\u3092\u304a\u52e7\u3081\u3057\u307e\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-151\">\n<p>\u30001. \u65e2\u5b58\u306e\u30b3\u30fc\u30c9\u3092\u30ec\u30d3\u30e5\u30fc\u3057\u3001\u6587\u5b57\u5217\u6bd4\u8f03\u306e\u5b9f\u88c5\u3092\u898b\u76f4\u3059<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-152\">\n<p>\u30002. \u30e6\u30cb\u30c3\u30c8\u30c6\u30b9\u30c8\u3092\u8ffd\u52a0\u3057\u3066\u3001\u6bd4\u8f03\u30ed\u30b8\u30c3\u30af\u306e\u4fe1\u983c\u6027\u3092\u78ba\u4fdd<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-153\">\n<p>\u30003. \u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3068\u30bb\u30ad\u30e5\u30ea\u30c6\u30a3\u306e\u89b3\u70b9\u304b\u3089\u6700\u9069\u5316\u3092\u691c\u8a0e<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-154\">\n<p>\u3088\u308a\u8a73\u3057\u3044\u5b66\u7fd2\u306e\u305f\u3081\u306b\u3001\u4ee5\u4e0b\u306e\u30ea\u30bd\u30fc\u30b9\u3082\u304a\u52e7\u3081\u3067\u3059\u3002<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-155\">\n<p>\u3000\u25cf Java API Documentation\uff08String \u30af\u30e9\u30b9\uff09<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-156\">\n<p>\u3000\u25cf JUnit \u306e\u30c9\u30ad\u30e5\u30e1\u30f3\u30c8\uff08\u30c6\u30b9\u30c8\u5b9f\u88c5\u306e\u8a73\u7d30\uff09<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-157\">\n<p>\u3000\u25cf Java Security Guidelines\uff08\u30bb\u30ad\u30e5\u30a2\u306a\u30b3\u30fc\u30c7\u30a3\u30f3\u30b0\uff09<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-158\">\n<h3 class=\"wp-block-heading\" id=\"i-24\">\u6700\u5f8c\u306b<\/h3>\n<\/div>\n\n\n<p>\u6587\u5b57\u5217\u6bd4\u8f03\u306f\u3001Java\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u306e\u57fa\u790e\u3067\u3042\u308a\u306a\u304c\u3089\u3001\u9069\u5207\u306a\u5b9f\u88c5\u306b\u306f\u69d8\u3005\u306a\u77e5\u8b58\u3068\u8003\u616e\u304c\u5fc5\u8981\u3067\u3059\u3002\u3053\u306e\u8a18\u4e8b\u3067\u89e3\u8aac\u3057\u305f\u5185\u5bb9\u3092\u57fa\u306b\u3001\u8981\u4ef6\u306b\u5fdc\u3058\u3066\u6700\u9069\u306a\u5b9f\u88c5\u3092\u9078\u629e\u3057\u3066\u304f\u3060\u3055\u3044\u3002\u7279\u306b\u91cd\u8981\u306a\u306e\u306f\u4ee5\u4e0b\u306e3\u70b9\u3067\u3059\u3002<\/p>\n\n\n<div id=\"sgb-css-id-159\">\n<p>\u30001. \u57fa\u672c\u306b\u5fe0\u5b9f\u3067\u3042\u308b\u3053\u3068\uff08<code>equals()<\/code>\u306e\u9069\u5207\u306a\u4f7f\u7528\uff09<\/p>\n<\/div>\n\n<div id=\"sgb-css-id-160\">\n<p>\u30002. \u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u610f\u8b58\u3059\u308b\u3053\u3068\uff08\u72b6\u6cc1\u306b\u5fdc\u3058\u305f\u6700\u9069\u5316\uff09<\/p>\n<\/div>\n\n\n<p>\u30003. \u30bb\u30ad\u30e5\u30ea\u30c6\u30a3\u3092\u8003\u616e\u3059\u308b\u3053\u3068\uff08\u8106\u5f31\u6027\u306e\u9632\u6b62\uff09<\/p>\n\n\n<div id=\"sgb-css-id-161\">\n<p>\u3053\u308c\u3089\u306e\u70b9\u3092\u610f\u8b58\u3057\u306a\u304c\u3089\u3001\u3088\u308a\u826f\u3044\u30b3\u30fc\u30c9\u3092\u66f8\u3044\u3066\u3044\u3063\u3066\u304f\u3060\u3055\u3044\u3002\u3088\u308a\u826f\u3044Java\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u306e\u5b9f\u8df5\u306b\u5411\u3051\u3066\u3001\u5b66\u3093\u3067\u3044\u304d\u307e\u3057\u3087\u3046\u3002<\/p>\n<\/div>\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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