{"id":913,"date":"2022-10-19T00:35:23","date_gmt":"2023-03-13T16:05:58","guid":{"rendered":"https:\/\/www.silicloud.com\/ja\/blog\/index.php\/2023\/11\/30\/java%e3%81%aestring%e3%82%af%e3%82%a4%e3%82%ba\/"},"modified":"2025-08-01T03:29:49","modified_gmt":"2025-07-31T18:29:49","slug":"java%e3%81%aestring%e3%82%af%e3%82%a4%e3%82%ba","status":"publish","type":"post","link":"https:\/\/www.silicloud.com\/ja\/blog\/java%e3%81%aestring%e3%82%af%e3%82%a4%e3%82%ba\/","title":{"rendered":"Java\u306eString\u30af\u30a4\u30ba"},"content":{"rendered":"<p>Java String Quiz\u3078\u3088\u3046\u3053\u305d\u3002String\u306fJava\u3067\u6700\u3082\u91cd\u8981\u306a\u30af\u30e9\u30b9\u306e\u4e00\u3064\u3067\u3059\u3002\u3082\u3057Java\u3067\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u3092\u4f55\u304b\u3057\u3089\u884c\u3063\u305f\u3053\u3068\u304c\u3042\u308c\u3070\u3001\u5fc5\u305a\u4f7f\u7528\u3057\u305f\u3053\u3068\u304c\u3042\u308b\u3067\u3057\u3087\u3046\u3002<\/p>\n<p>Java\u306e\u9762\u63a5\u3084\u30af\u30a4\u30ba\u306e\u554f\u984c\u3068\u3057\u3066\u3001\u6587\u5b57\u5217\u306f\u975e\u5e38\u306b\u4eba\u6c17\u304c\u3042\u308a\u307e\u3059\u3002\u3067\u3059\u306e\u3067\u3001\u79c1\u306f\u3044\u304f\u3064\u304b\u306e\u7d20\u6674\u3089\u3057\u3044\u3001\u305d\u3057\u3066\u30c8\u30ea\u30c3\u30ad\u30fc\u306aJava\u6587\u5b57\u5217\u30af\u30a4\u30ba\u306e\u554f\u984c\u3092\u96c6\u3081\u307e\u3057\u305f\u3002\u8a66\u3057\u3066\u307f\u308b\u3079\u304d\u3067\u3059\u3002<\/p>\n<h2>Java\u306eString\u30af\u30a4\u30ba<\/h2>\n<p>\u3053\u306e\u30af\u30a4\u30ba\u306b\u306f21\u306e\u8cea\u554f\u304c\u3042\u308a\u307e\u3059\u3002\u3082\u305715\u500b\u4ee5\u4e0a\u6b63\u3057\u304f\u7b54\u3048\u308b\u3053\u3068\u304c\u3067\u304d\u305f\u3089\u3001\u3042\u306a\u305f\u306f\u6587\u5b57\u5217\u306e\u6982\u5ff5\u306b\u3068\u3066\u3082\u512a\u308c\u3066\u3044\u308b\u3068\u8003\u3048\u3066\u304f\u3060\u3055\u3044\u3002\u5404\u8cea\u554f\u306e\u5f8c\u306b\u300c\u56de\u7b54\u3092\u8868\u793a\u3059\u308b\u300d\u30dc\u30bf\u30f3\u3092\u30af\u30ea\u30c3\u30af\u3059\u308b\u3053\u3068\u3067\u7b54\u3048\u3068\u8a73\u3057\u3044\u8aac\u660e\u3092\u78ba\u8a8d\u3067\u304d\u307e\u3059\u3002<\/p>\n<p>\u300c\u30b9\u30c8\u30ea\u30f3\u30b0\u30af\u30a4\u30ba\u3092\u59cb\u3081\u307e\u3057\u3087\u3046\u3002\u5e78\u904b\u3092\u304a\u7948\u308a\u3057\u307e\u3059\u3002\u300d<\/p>\n<h4>\u4ee5\u4e0b\u306e\u30b9\u30c6\u30fc\u30c8\u30e1\u30f3\u30c8\u306e\u51fa\u529b\u306f\u4f55\u306b\u306a\u308a\u307e\u3059\u304b\uff1f<\/h4>\n<pre class=\"post-pre\"><code>String s = \"Java String Quiz\";\r\nSystem.out.println(s.charAt(s.toUpperCase().length()));\r\n<\/code><\/pre>\n<p>A. \u300cZ\u300d\u309290\u306e\u6574\u6570\u306b\u5909\u63db\u3057\u3001\u300c90\u300d\u3068\u8868\u793a\u3057\u307e\u3059\u3002<br \/>\nB. \u5b9f\u884c\u6642\u4f8b\u5916<br \/>\nC. \u300cz\u300d\u3068\u8868\u793a\u3057\u307e\u3059\u3002<br \/>\nD. \u300cZ\u300d\u3068\u8868\u793a\u3057\u307e\u3059\u3002<\/p>\n<details>\u56de\u7b54\u3092\u8868\u793a\u3059\u308b\u306b\u306f\u30af\u30ea\u30c3\u30af\u3057\u3066\u304f\u3060\u3055\u3044\u3002\u6b63\u3057\u3044\u7b54\u3048\uff1aB<br \/>\n\u30e9\u30f3\u30bf\u30a4\u30e0\u4f8b\u5916\u304c\u767a\u751f\u3057\u307e\u3059\u3002\u30b9\u30ec\u30c3\u30c9\u300cmain\u300d\u306e\u4e2d\u3067\u4f8b\u5916\u304c\u767a\u751f\u3057\u307e\u3057\u305f\u3002java.lang.StringIndexOutOfBoundsException\uff1a\u6587\u5b57\u5217\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u304c\u7bc4\u56f2\u5916\u3067\u3059\uff1a16\u3053\u308c\u306f\u3001\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u306e\u5024\u304c0\u304b\u3089\u59cb\u307e\u308b\u305f\u3081\u3067\u3059\u3002<\/details>\n<h4>2. \u4ee5\u4e0b\u306e\u6587\u306e\u51fa\u529b\u306f\u4f55\u306b\u306a\u308a\u307e\u3059\u304b\uff1f<\/h4>\n<pre class=\"post-pre\"><code>String s = \"Java String Quiz\";\r\nSystem.out.println(s.substring(5,3));\r\n<\/code><\/pre>\n<p>A. &#8220;Str&#8221; \u306e\u30d7\u30ea\u30f3\u30c8<br \/>\nB. \u30e9\u30f3\u30bf\u30a4\u30e0\u30a8\u30e9\u30fc<br \/>\nC. \u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u304c\u7bc4\u56f2\u5916\u3067\u3059 \u30e9\u30f3\u30bf\u30a4\u30e0\u30a8\u30e9\u30fc<br \/>\nD. \u6587\u5b57\u5217\u306e\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u304c\u7bc4\u56f2\u5916\u3067\u3059 \u30b3\u30f3\u30d1\u30a4\u30eb\u6642\u30a8\u30e9\u30fc<\/p>\n<details>\u7b54\u3048\u3092\u8868\u793a\u3059\u308b\u305f\u3081\u306b\u30af\u30ea\u30c3\u30af\u3057\u3066\u304f\u3060\u3055\u3044\u3002<br \/>\n\u6b63\u89e3\uff1aB<br \/>\n\u30a8\u30e9\u30fc\u30e1\u30c3\u30bb\u30fc\u30b8\u3068\u3057\u3066Exception in thread &#8220;main&#8221; java.lang.StringIndexOutOfBoundsException: begin 5, end 3, length 16\u3068\u3068\u3082\u306b\u30e9\u30f3\u30bf\u30a4\u30e0\u4f8b\u5916\u304c\u30b9\u30ed\u30fc\u3055\u308c\u307e\u3059\u3002\u3053\u308c\u306f\u3001\u7d42\u4e86\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u304c\u958b\u59cb\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u3088\u308a\u3082\u5c0f\u3055\u3044\u305f\u3081\u3067\u3059\u3002<\/details>\n<h4>3. String\u30af\u30e9\u30b9\u306e\u6709\u52b9\u306a\u30e1\u30bd\u30c3\u30c9\u3092\u3059\u3079\u3066\u9078\u629e\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/h4>\n<p>A. trim() &#8211; \u30c8\u30ea\u30df\u30f3\u30b0\u3059\u308b<br \/>\nB. intern() &#8211; \u6587\u5b57\u5217\u3092\u30a4\u30f3\u30bf\u30fc\u30f3\u306b\u3059\u308b<br \/>\nC. toLower() &#8211; \u5c0f\u6587\u5b57\u306b\u5909\u63db\u3059\u308b<br \/>\nD. split() &#8211; \u5206\u5272\u3059\u308b<\/p>\n<details>String\u30af\u30e9\u30b9\u306e\u6709\u52b9\u306a\u30e1\u30bd\u30c3\u30c9\u306f\u3001trim()\u3001intern()\u3001toLowerCase()\u3001\u304a\u3088\u3073split(String regex)\u3067\u3059\u3002<\/details>\n<h4>4. \u4e0b\u8a18\u306e\u6587\u306e\u51fa\u529b\u306f\u4f55\u306b\u306a\u308a\u307e\u3059\u304b\uff1f<\/h4>\n<pre class=\"post-pre\"><code>String s1 = \"Cat\";\r\nString s2 = \"Cat\";\r\nString s3 = new String(\"Cat\");\r\nSystem.out.print(s1 == s2);\r\nSystem.out.print(s1 == s3);\r\n<\/code><\/pre>\n<p>A. \u771f\u507d (\u3057\u3093\u304e)<br \/>\nB. \u771f\u771f (\u3057\u3093\u3057\u3093)<br \/>\nC. \u507d\u507d (\u304e\u304e)<br \/>\nD. \u507d\u771f (\u304e\u3057\u3093)<\/p>\n<details>\u30c0\u30d6\u30eb\u30af\u30a9\u30fc\u30c8\u3092\u4f7f\u7528\u3057\u3066String\u3092\u4f5c\u6210\u3059\u308b\u5834\u5408\u3001\u307e\u305aString\u30d7\u30fc\u30eb\u5185\u3067\u540c\u3058\u5024\u306eString\u3092\u63a2\u3057\u307e\u3059\u3002\u898b\u3064\u304b\u3063\u305f\u5834\u5408\u306f\u3001\u53c2\u7167\u3092\u8fd4\u3057\u307e\u3059\u3002\u898b\u3064\u304b\u3089\u306a\u304b\u3063\u305f\u5834\u5408\u306f\u3001\u65b0\u3057\u3044String\u3092\u30d7\u30fc\u30eb\u306b\u4f5c\u6210\u3057\u3001\u305d\u306e\u5f8c\u53c2\u7167\u3092\u8fd4\u3057\u307e\u3059\u3002<br \/>\n\u4e00\u65b9\u3001new\u6f14\u7b97\u5b50\u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u3067\u3001String\u30af\u30e9\u30b9\u306b\u5f37\u5236\u7684\u306b\u30d2\u30fc\u30d7\u9818\u57df\u306b\u65b0\u3057\u3044String\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u4f5c\u6210\u3055\u305b\u307e\u3059\u3002\u305d\u306e\u305f\u3081\u3001s1\u3068s2\u306f\u30d7\u30fc\u30eb\u5185\u306e\u540c\u3058String\u3078\u306e\u53c2\u7167\u3092\u6301\u3061\u307e\u3059\u304c\u3001s3\u306f\u30d7\u30fc\u30eb\u5916\u306e\u5225\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306b\u306a\u308b\u305f\u3081\u3001\u51fa\u529b\u304c\u7570\u306a\u308b\u3067\u3059\u3002<\/details>\n<h4>5. \u30b9\u30a4\u30c3\u30c1\u30b1\u30fc\u30b9\u306b\u304a\u3044\u3066\u3001\u4ee5\u4e0b\u306e\u6587\u306f\u3069\u308c\u304c\u771f\u3067\u3059\u304b\uff1f<\/h4>\n<p>A. Java 1.5\u4ee5\u964d\u306e\u30d0\u30fc\u30b8\u30e7\u30f3\u3067\u306f\u3001switch case\u5185\u3067\u6587\u5b57\u5217\u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u304c\u8a31\u53ef\u3055\u308c\u3066\u3044\u307e\u3059\u3002<br \/>\nB. Java 1.7\u4ee5\u964d\u306e\u30d0\u30fc\u30b8\u30e7\u30f3\u3067\u306f\u3001switch case\u5185\u3067\u6587\u5b57\u5217\u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u304c\u8a31\u53ef\u3055\u308c\u3066\u3044\u307e\u3059\u3002<br \/>\nC. switch-case\u306e\u5b9f\u88c5\u3067\u306fequals()\u30e1\u30bd\u30c3\u30c9\u304c\u4f7f\u7528\u3055\u308c\u308b\u305f\u3081\u3001NullPointerException\u3092\u907f\u3051\u308b\u305f\u3081\u306bnull\u30c1\u30a7\u30c3\u30af\u3092\u8ffd\u52a0\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n<details>\u4ee5\u4e0b\u306e\u6587\u3092\u65e5\u672c\u8a9e\u3067\u81ea\u7136\u306b\u8a00\u3044\u63db\u3048\u3066\u304f\u3060\u3055\u3044\u3002\u4e00\u3064\u306e\u30aa\u30d7\u30b7\u30e7\u30f3\u306e\u307f\u3067\u5927\u4e08\u592b\u3067\u3059\uff1a\u7b54\u3048\u3092\u8868\u793a\u3059\u308b\u306b\u306f\u30af\u30ea\u30c3\u30af\u3057\u3066\u304f\u3060\u3055\u3044<br \/>\n\u6b63\u89e3\uff1aB\u3001C<br \/>\njava switch case string\u3067\u8a73\u7d30\u3092\u8aad\u3080<\/p>\n<\/details>\n<h4>\uff16. StringBuffer\u3068StringBuilder\u306b\u3064\u3044\u3066\u3001\u4ee5\u4e0b\u306e\u6587\u306e\u3046\u3061\u771f\u5b9f\u3067\u3042\u308b\u3082\u306e\u306f\u3069\u308c\u3067\u3059\u304b\uff1f<\/h4>\n<p>A. StringBuilder\u306f\u30b9\u30ec\u30c3\u30c9\u30bb\u30fc\u30d5\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002<br \/>\nB. StringBuffer\u306f\u3001\u30e1\u30bd\u30c3\u30c9\u304c\u540c\u671f\u3055\u308c\u3066\u3044\u308b\u305f\u3081\u3001\u30b9\u30ec\u30c3\u30c9\u30bb\u30fc\u30d5\u3067\u3059\u3002<br \/>\nC. StringBuilder\u306fJava 1.4\u3067\u5c0e\u5165\u3055\u308c\u307e\u3057\u305f\u3002<br \/>\nD. StringBuffer\u3068StringBuilder\u306f\u4e0d\u5909\u3067\u3059\u3002<\/p>\n<details>\u4ee5\u4e0b\u306e\u7b54\u3048\u3092\u30af\u30ea\u30c3\u30af\u3057\u3066\u8868\u793a\u3057\u3066\u304f\u3060\u3055\u3044\uff1a\u6b63\u3057\u3044\u7b54\u3048\uff1aA\u3001B<br \/>\nStringBuffer\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306f\u3001\u30e1\u30bd\u30c3\u30c9\u304c\u540c\u671f\u3055\u308c\u3066\u3044\u308b\u305f\u3081\u30b9\u30ec\u30c3\u30c9\u30bb\u30fc\u30d5\u3067\u3059\u3002\u3057\u304b\u3057\u3001\u307b\u3068\u3093\u3069\u306e\u5834\u5408\u306b\u304a\u3044\u3066\u306f\u30aa\u30fc\u30d0\u30fc\u30d8\u30c3\u30c9\u3068\u306a\u308b\u305f\u3081\u3001Java 1.5\u3067StringBuilder\u304c\u5c0e\u5165\u3055\u308c\u307e\u3057\u305f\u3002StringBuilder\u306f\u30b9\u30ec\u30c3\u30c9\u30bb\u30fc\u30d5\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002StringBuffer\u3068StringBuilder\u306f\u5909\u66f4\u53ef\u80fd\u306a\u30af\u30e9\u30b9\u3067\u3059\u3002String vs. StringBuffer vs. StringBuilder\u3067\u8a73\u7d30\u3092\u8aad\u3093\u3067\u304f\u3060\u3055\u3044\u3002<\/details>\n<h4>7. \u4ee5\u4e0b\u306e\u30c7\u30b6\u30a4\u30f3\u30d1\u30bf\u30fc\u30f3\u306e\u4e2d\u3067\u3001\u6587\u5b57\u5217\u306e\u5b9f\u88c5\u306f\u3069\u308c\u306b\u5f93\u3044\u307e\u3059\u304b\uff1f<\/h4>\n<p>A. \u30d5\u30e9\u30a4\u30a6\u30a7\u30a4\u30c8\u30c7\u30b6\u30a4\u30f3\u30d1\u30bf\u30fc\u30f3<br \/>\nB. \u30d5\u30a1\u30af\u30c8\u30ea\u30fc\u30d1\u30bf\u30fc\u30f3<br \/>\nC. \u30b7\u30f3\u30b0\u30eb\u30c8\u30f3\u30d1\u30bf\u30fc\u30f3<br \/>\nD. \u4e0a\u8a18\u306e\u3069\u308c\u3067\u3082\u306a\u3044<\/p>\n<details>\u6b63\u89e3\uff1aA<br \/>\n\u6587\u5b57\u5217\u30d7\u30fc\u30eb\u306e\u5b9f\u88c5\u306f\u30d5\u30e9\u30a4\u30a6\u30a7\u30a4\u30c8\u30c7\u30b6\u30a4\u30f3\u30d1\u30bf\u30fc\u30f3\u306b\u5f93\u3044\u307e\u3059\u3002<\/details>\n<h4>\uff18. \u4ee5\u4e0b\u306e\u30b9\u30c6\u30fc\u30c8\u30e1\u30f3\u30c8\u306e\u51fa\u529b\u306f\u4f55\u306b\u306a\u308a\u307e\u3059\u304b\uff1f<\/h4>\n<pre class=\"post-pre\"><code>String s1 = \"abc\";\r\nString s2 = \"def\";\r\nSystem.out.println(s1.compareTo(s2));\r\n<\/code><\/pre>\n<p>A. \u3007 (maru)<br \/>\nB. \u771f (makoto)<br \/>\nC. -3 (ma-i no san)<br \/>\nD. \u507d (uso)<\/p>\n<details>String\u30af\u30e9\u30b9\u306ecompareTo()\u30e1\u30bd\u30c3\u30c9\u306e\u30c9\u30ad\u30e5\u30e1\u30f3\u30c8\u304b\u3089\uff1a<br \/>\ncompareTo\u30e1\u30bd\u30c3\u30c9\u306f\u30012\u3064\u306e\u6587\u5b57\u5217\u3092\u8f9e\u66f8\u9806\u306b\u6bd4\u8f03\u3057\u307e\u3059\u3002\u6bd4\u8f03\u306f\u3001\u6587\u5b57\u5217\u5185\u306e\u5404\u6587\u5b57\u306eUnicode\u5024\u306b\u57fa\u3065\u3044\u3066\u884c\u308f\u308c\u307e\u3059\u3002\u3053\u306eString\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306b\u3088\u3063\u3066\u8868\u3055\u308c\u308b\u6587\u5b57\u5217\u306e\u30b7\u30fc\u30b1\u30f3\u30b9\u306f\u3001\u5f15\u6570\u306e\u6587\u5b57\u5217\u306b\u3088\u3063\u3066\u8868\u3055\u308c\u308b\u6587\u5b57\u5217\u306e\u30b7\u30fc\u30b1\u30f3\u30b9\u3068\u8f9e\u66f8\u9806\u306b\u6bd4\u8f03\u3055\u308c\u307e\u3059\u3002\u7d50\u679c\u306f\u3001\u3053\u306eString\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u304c\u5f15\u6570\u306e\u6587\u5b57\u5217\u3088\u308a\u3082\u8f9e\u66f8\u9806\u3067\u5148\u884c\u3059\u308b\u5834\u5408\u306b\u306f\u8ca0\u306e\u6574\u6570\u3001\u8f9e\u66f8\u9806\u3067\u5f8c\u7d9a\u3059\u308b\u5834\u5408\u306b\u306f\u6b63\u306e\u6574\u6570\u3001\u6587\u5b57\u5217\u304c\u7b49\u3057\u3044\u5834\u5408\u306b\u306f\u30bc\u30ed\u3067\u3059\u3002compareTo\u306f\u3001\u6587\u5b57\u5217\u304c\u7b49\u3057\u3044\u5834\u5408\u306b\u306f\u6b63\u78ba\u306bequals(Object)\u30e1\u30bd\u30c3\u30c9\u304ctrue\u3092\u8fd4\u3059\u5834\u5408\u306b0\u3092\u8fd4\u3057\u307e\u3059\u3002<br \/>\n\u3053\u308c\u304c\u8f9e\u66f8\u9806\u306e\u5b9a\u7fa9\u3067\u3059\u30022\u3064\u306e\u6587\u5b57\u5217\u304c\u7570\u306a\u308b\u5834\u5408\u3001\u305d\u308c\u305e\u308c\u306e\u6587\u5b57\u5217\u306e\u6709\u52b9\u306a\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u3067\u7570\u306a\u308b\u6587\u5b57\u304c\u5b58\u5728\u3059\u308b\u304b\u3001\u6587\u5b57\u5217\u306e\u9577\u3055\u304c\u7570\u306a\u308b\u304b\u3001\u307e\u305f\u306f\u4e21\u65b9\u304c\u8a72\u5f53\u3057\u307e\u3059\u30021\u3064\u4ee5\u4e0a\u306e\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u4f4d\u7f6e\u3067\u7570\u306a\u308b\u6587\u5b57\u304c\u5b58\u5728\u3059\u308b\u5834\u5408\u3001\u6700\u5c0f\u306e\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u3092k\u3068\u3059\u308b\u3068\u3001\u4f4d\u7f6ek\u306e\u6587\u5b57\u306e\u5024\u304c\u5c0f\u3055\u3044\u65b9\u306e\u6587\u5b57\u5217\u304c\u3001&lt;\u6f14\u7b97\u5b50\u3092\u4f7f\u7528\u3057\u3066\u8f9e\u66f8\u9806\u3067\u5148\u884c\u3057\u307e\u3059\u3002\u3053\u306e\u5834\u5408\u3001compareTo\u306f\u30012\u3064\u306e\u6587\u5b57\u5217\u306e\u4f4d\u7f6ek\u3067\u306e\u6587\u5b57\u5024\u306e\u5dee\u3001\u3064\u307e\u308a\u4ee5\u4e0b\u306e\u5024\u3092\u8fd4\u3057\u307e\u3059\uff1a<br \/>\nthis.charAt(k)-anotherString.charAt(k)<br \/>\n\u4f8b\u3067\u306f\u3001&#8221;abc&#8221;\u306f&#8221;def&#8221;\u3088\u308a\u3082\u5148\u884c\u3059\u308b\u305f\u3081\u3001\u8ca0\u306e\u6574\u6570\u304c\u8fd4\u3055\u308c\u307e\u3059\u3002\u6b21\u306b\u3001\u7570\u306a\u308b\u6587\u5b57\u304c\u5b58\u5728\u3059\u308b\u6700\u3082\u5c0f\u3055\u3044\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u3067\u3042\u308b0\u3068\u3001a\u304b\u3089d\u307e\u3067\u304c-3\u3068\u7b49\u3057\u3044\u3067\u3059\u3002<\/details>\n<h4>\u4ee5\u4e0b\u306e\u30d7\u30ed\u30b0\u30e9\u30e0\u306e\u51fa\u529b\u306f\u4f55\u306b\u306a\u308a\u307e\u3059\u304b\uff1f<\/h4>\n<pre class=\"post-pre\"><code>public class Test {\r\n\tpublic static void main(String[] args) {\r\n\t\tString x = \"abc\";\r\n\t\tString y = \"abc\";\r\n\t\tx.concat(y);\r\n\t\tSystem.out.print(x);\r\n\t}\r\n}\r\n<\/code><\/pre>\n<p>A. \u3042\u308b\u3044\u306f\u3001A.\u3000\u30a2\u30eb\u30d5\u30a1\u30d9\u30c3\u30c8<br \/>\nB.\u3000\u3042\u308b\u3044\u306f\u3001A. \u30a2\u30eb\u30d5\u30a1\u30d9\u30c3\u30c8\u30a2\u30eb\u30d5\u30a1\u30d9\u30c3\u30c8<br \/>\nC.\u3000\u3042\u308b\u3044\u306f\u3001C. \u30cc\u30eb<\/p>\n<details>\u300cx.concat(y)\u300d\u306f\u65b0\u3057\u3044\u6587\u5b57\u5217\u3092\u4f5c\u6210\u3057\u307e\u3059\u304c\u3001x\u306b\u306f\u5272\u308a\u5f53\u3066\u3089\u308c\u3066\u3044\u307e\u305b\u3093\u306e\u3067\u3001x\u306e\u5024\u306f\u5909\u66f4\u3055\u308c\u307e\u305b\u3093\u3002<\/details>\n<h4>10. \u4ee5\u4e0b\u306e\u30d7\u30ed\u30b0\u30e9\u30e0\u306e\u51fa\u529b\u306f\u4f55\u306b\u306a\u308a\u307e\u3059\u304b\uff1f<\/h4>\n<pre class=\"post-pre\"><code>public class Test {\r\n\tpublic static void main(String[] args) {\r\n\t\tString s1 = \"abc\";\r\n\t\tString s2 = \"abc\";\r\n\t\tSystem.out.println(\"s1 == s2 is:\" + s1 == s2);\r\n\t}\r\n}\r\n<\/code><\/pre>\n<p>A. \u507d (\u304e)<br \/>\nB. s1\u3068s2\u304c\u7b49\u3057\u3044:true (s1\u3068s2\u304c\u3072\u3068\u3057\u3044\u3068:true)<br \/>\nC. s1\u3068s2\u304c\u7b49\u3057\u3044:false (s1\u3068s2\u304c\u3072\u3068\u3057\u3044\u3068:false)<br \/>\nD. \u771f (\u3057\u3093)<\/p>\n<details>\u30af\u30ea\u30c3\u30af\u3057\u3066\u56de\u7b54\u3092\u8868\u793a\u3059\u308b<br \/>\n\u6b63\u3057\u3044\u56de\u7b54\uff1aA<br \/>\nJava\u3067\u306f\u3001+\u6f14\u7b97\u5b50\u306e\u512a\u5148\u5ea6\u304c==\u6f14\u7b97\u5b50\u3088\u308a\u3082\u9ad8\u3044\u305f\u3081\u3001\u4e0e\u3048\u3089\u308c\u305f\u6587\u306e\u51fa\u529b\u306f\u300cfalse\u300d\u306b\u306a\u308a\u307e\u3059\u3002\u3057\u305f\u304c\u3063\u3066\u3001\u4e0e\u3048\u3089\u308c\u305f\u5f0f\u306f\u300cs1 == s2 \u306f:abc\u300d==\u300cabc\u300d\u3068\u8a55\u4fa1\u3055\u308c\u3001\u3064\u307e\u308afalse\u3068\u306a\u308a\u307e\u3059\u3002<\/details>\n<h4>11. \u4ee5\u4e0b\u306e\u30b9\u30c6\u30fc\u30c8\u30e1\u30f3\u30c8\u306e\u51fa\u529b\u306f\u4f55\u306b\u306a\u308a\u307e\u3059\u304b\uff1f<\/h4>\n<pre class=\"post-pre\"><code>String s = \"Java\"+1+2+\"Quiz\"+\"\"+(3+4);\r\nSystem.out.println(s);\r\n<\/code><\/pre>\n<p>A. \u30b8\u30e3\u30d03\u30af\u30a4\u30ba7<br \/>\nB. \u30b8\u30e3\u30d012\u30af\u30a4\u30ba7<br \/>\nC. \u30b8\u30e3\u30d012\u30af\u30a4\u30ba34<br \/>\nD. \u30b8\u30e3\u30d03\u30af\u30a4\u30ba34<\/p>\n<details>\u307e\u305a\u3001\u304b\u3063\u3053\u5185\u306e\u5f0f\u304c\u5b9f\u884c\u3055\u308c\u307e\u3059\u3002\u305d\u308c\u304b\u3089\u3001\u5168\u3066\u306e + \u6f14\u7b97\u5b50\u304c\u5b9f\u884c\u3055\u308c\u3001\u5de6\u304b\u3089\u53f3\u3078\u3068\u51e6\u7406\u3055\u308c\u307e\u3059\u3002<br \/>\n\u5404\u7d50\u5408\u3054\u3068\u306b\u6587\u5b57\u5217\u304c\u5f97\u3089\u308c\u308b\u305f\u3081\u3001\u4e0b\u8a18\u306e\u3088\u3046\u306b\u51fa\u529b\u304c\u751f\u6210\u3055\u308c\u307e\u3059\u3002<br \/>\n\u201cJava\u201d+1+2+\u201cQuiz\u201d+\u201c\u201d+(3+4)<br \/>\n= \u201cJava\u201d+1+2+\u201cQuiz\u201d+\u201c\u201d+7<br \/>\n= \u201cJava1\u201d+2+\u201cQuiz\u201d+\u201c\u201d+7<br \/>\n= \u201cJava12\u201d+\u201cQuiz\u201d+\u201c\u201d+7<br \/>\n= \u201cJava12Quiz\u201d+\u201c\u201d+7<br \/>\n= \u201cJava12Quiz\u201d+7<br \/>\n= \u201cJava12Quiz7\u201d<\/details>\n<h4>12. \u4ee5\u4e0b\u306e\u6587\u3067\u4f5c\u6210\u3055\u308c\u308bString\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306f\u3044\u304f\u3064\u3042\u308a\u307e\u3059\u304b\uff1f<\/h4>\n<pre class=\"post-pre\"><code>String s = \"abc\"; \/\/ statement 1\r\nString s1 = new String(\"abcd\"); \/\/ statement 2\r\n<\/code><\/pre>\n<p>A. 1 &#8211; \u3044\u3061<br \/>\nB. 2 &#8211; \u306b<br \/>\nC. 3 &#8211; \u3055\u3093<br \/>\nD. 4 &#8211; \u3088\u3093<\/p>\n<details>\u7b54\u3048\u3092\u8868\u793a\u3059\u308b\u306b\u306f\u30af\u30ea\u30c3\u30af\u3057\u3066\u304f\u3060\u3055\u3044<br \/>\n\u6b63\u3057\u3044\u7b54\u3048\uff1aC<br \/>\n1\u756a\u76ee\u306e\u6587\u3067\u306f\u3001\u6587\u5b57\u5217\u30d7\u30fc\u30eb\u3067\u300cabc\u300d\u304c\u4f5c\u6210\u3055\u308c\u307e\u3059\u3002<br \/>\n2\u756a\u76ee\u306e\u6587\u3067\u306f\u3001\u307e\u305a\u6587\u5b57\u5217\u30d7\u30fc\u30eb\u3067\u300cabcd\u300d\u304c\u4f5c\u6210\u3055\u308c\u307e\u3059\u3002\u305d\u308c\u304cString new\u6f14\u7b97\u5b50\u306e\u5f15\u6570\u3068\u3057\u3066\u6e21\u3055\u308c\u3001\u5225\u306e\u6587\u5b57\u5217\u304c\u30d2\u30fc\u30d7\u30e1\u30e2\u30ea\u306b\u4f5c\u6210\u3055\u308c\u307e\u3059\u3002<br \/>\n\u3057\u305f\u304c\u3063\u3066\u3001\u5408\u8a083\u3064\u306e\u6587\u5b57\u5217\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u304c\u4f5c\u6210\u3055\u308c\u307e\u3059\u3002<\/details>\n<h4>13. \u4ee5\u4e0b\u306e\u30b9\u30c6\u30fc\u30c8\u30e1\u30f3\u30c8\u306e\u51fa\u529b\u306f\u4f55\u306b\u306a\u308a\u307e\u3059\u304b\uff1f<\/h4>\n<pre class=\"post-pre\"><code>String s1 = \"abc\";\r\nString s2 = new String(\"abc\");\r\nSystem.out.print(s1==s2);\r\nSystem.out.println(s1==s2.intern());\r\n<\/code><\/pre>\n<p>A. \u507d\u308a\u771f (\u3044\u3064\u308f\u308a\u307e\u3053\u3068)<br \/>\nB. \u507d\u308a\u507d (\u3044\u3064\u308f\u308a\u3044\u3064\u308f\u308a)<br \/>\nC. \u771f\u771f (\u307e\u3053\u3068\u307e\u3053\u3068)<br \/>\nD. \u771f\u507d (\u307e\u3053\u3068\u3044\u3064\u308f\u308a)<\/p>\n<details>s1\u306f\u6587\u5b57\u5217\u30d7\u30fc\u30eb\u306b\u3042\u308a\u3001s2\u306f\u30d2\u30fc\u30d7\u30e1\u30e2\u30ea\u3067\u4f5c\u6210\u3055\u308c\u307e\u3059\u3002<br \/>\n\u3057\u305f\u304c\u3063\u3066\u3001s1==s2\u306ffalse\u3092\u8fd4\u3057\u307e\u3059\u3002<br \/>\ns2.intern()\u30e1\u30bd\u30c3\u30c9\u304c\u547c\u3073\u51fa\u3055\u308c\u308b\u3068\u3001\u30d7\u30fc\u30eb\u5185\u306b\u5024\u304c\u300cabc\u300d\u306e\u6587\u5b57\u5217\u304c\u3042\u308b\u304b\u3069\u3046\u304b\u3092\u78ba\u8a8d\u3057\u307e\u3059\u3002\u3057\u305f\u304c\u3063\u3066\u3001s1\u306e\u53c2\u7167\u3092\u8fd4\u3057\u307e\u3059\u3002\u3057\u305f\u304c\u3063\u3066\u3001\u4eca\u5ea6\u306fs1\u3068s2\u306e\u4e21\u65b9\u304c\u540c\u3058\u6587\u5b57\u5217\u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u3092\u6307\u3057\u3066\u3044\u307e\u3059\u3002<br \/>\n\u3057\u305f\u304c\u3063\u3066\u3001s1==s2.intern()\u306ftrue\u3092\u8fd4\u3057\u307e\u3059\u3002<\/details>\n<h4>14. String\u30af\u30e9\u30b9\u306b\u5b9f\u88c5\u3055\u308c\u3066\u3044\u308b\u3059\u3079\u3066\u306e\u30a4\u30f3\u30bf\u30fc\u30d5\u30a7\u30fc\u30b9\u3092\u9078\u629e\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/h4>\n<p>A. \u30b7\u30ea\u30a2\u30e9\u30a4\u30ba\u53ef\u80fd (shiriarizu kan\u014d)<br \/>\nB. \u6bd4\u8f03\u53ef\u80fd (hikaku kan\u014d)<br \/>\nC. \u7d50\u754c\u5b88 (kekkaishu)<br \/>\nD. \u30af\u30ed\u30fc\u30f3\u53ef\u80fd (kur\u014dn kan\u014d)<\/p>\n<details>\u6b21\u306e\u3088\u3046\u306b\u65e5\u672c\u8a9e\u3067\u8a00\u3044\u63db\u3048\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\uff1a<br \/>\n\u7b54\u3048\u3092\u8868\u793a\u3059\u308b\u306b\u306f\u3001\u30af\u30ea\u30c3\u30af\u3057\u307e\u3059\u3002<br \/>\n\u6b63\u89e3\uff1aA\u3001B\u3001C<br \/>\nString\u306f\u76f4\u5217\u5316\u304a\u3088\u3073\u6bd4\u8f03\u53ef\u80fd\u3067\u3059\u3002Constable\u306fJava 12\u306e\u30ea\u30ea\u30fc\u30b9\u3067\u65b0\u3057\u3044\u30a4\u30f3\u30bf\u30d5\u30a7\u30fc\u30b9\u3067\u3059\u3002<\/details>\n<h4>15. String\u3092Map\u306e\u30ad\u30fc\u306b\u3059\u308b\u306e\u306b\u7406\u7531\u3068\u306a\u308b\u3082\u306e\u3092\u3059\u3079\u3066\u9078\u629e\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/h4>\n<p>A. \u6587\u5b57\u5217\u306f\u5909\u66f4\u4e0d\u53ef\u80fd\u3067\u3059\u3002<br \/>\nB. \u6587\u5b57\u5217\u306f\u6700\u7d42\u7684\u3067\u3059\u3002<br \/>\nC. \u6587\u5b57\u5217\u306fhashCode()\u3068equals()\u30e1\u30bd\u30c3\u30c9\u3092\u6b63\u3057\u304f\u5b9f\u88c5\u3057\u3066\u3044\u307e\u3059\u3002<br \/>\nD. \u6587\u5b57\u5217\u306e\u30cf\u30c3\u30b7\u30e5\u30b3\u30fc\u30c9\u306f\u30ad\u30e3\u30c3\u30b7\u30e5\u3055\u308c\u3066\u3044\u307e\u3059\u3002<\/p>\n<details>\u6b63\u3057\u3044\u5b9f\u88c5\u3092\u884c\u3046\u305f\u3081\u306b\u306f\u3001hashCode()\u30e1\u30bd\u30c3\u30c9\u3068equals()\u30e1\u30bd\u30c3\u30c9\u306e\u9069\u5207\u306a\u5b9f\u88c5\u304c\u5fc5\u8981\u3067\u3059\u3002\u6587\u5b57\u5217\u306f\u6700\u7d42\u7684\u3067\u4e0d\u5909\u306a\u305f\u3081\u3001\u30ad\u30fc\u30c7\u30fc\u30bf\u306e\u7834\u640d\u306e\u53ef\u80fd\u6027\u306f\u3042\u308a\u307e\u305b\u3093\u3002<\/details>\n<h4>16. \u4ee5\u4e0b\u306e\u30b3\u30fc\u30c9\u30b9\u30cb\u30da\u30c3\u30c8\u306e\u51fa\u529b\u306f\u4f55\u306b\u306a\u308a\u307e\u3059\u304b\uff1f<\/h4>\n<pre class=\"post-pre\"><code>String s1 = new String(\"java\");\r\nString s2 = new String(\"JAVA\");\r\nSystem.out.println(s1 = s2);\r\n<\/code><\/pre>\n<p>A. JAVA<br \/>\nB. java<br \/>\nC. true<br \/>\nD. false<\/p>\n<p>A. \u30b8\u30e3\u30d0<br \/>\nB. \u30b8\u30e3\u30f4\u30a1<br \/>\nC. \u771f<br \/>\nD. \u507d<\/p>\n<details>println()\u30e1\u30bd\u30c3\u30c9\u306e\u5185\u90e8\u306b\u3042\u308b\u5f15\u6570\u304c\u4ee3\u5165\u3067\u3042\u308b\u305f\u3081\u3001\u300cJAVA\u300d\u3068\u8868\u793a\u3055\u308c\u307e\u3059\u3002\u3057\u305f\u304c\u3063\u3066\u3001\u305d\u308c\u306fSystem.out.println(&#8220;JAVA&#8221;)\u3068\u3057\u3066\u51e6\u7406\u3055\u308c\u308b\u3067\u3057\u3087\u3046\u3002<\/details>\n<h4>17. \u4ee5\u4e0b\u306e\u6587\u306e\u51fa\u529b\u306f\u4f55\u306b\u306a\u308a\u307e\u3059\u304b\uff1f<\/h4>\n<pre class=\"post-pre\"><code>String s1 = \"abc\";\r\nStringBuffer s2 = new StringBuffer(s1);\r\nSystem.out.println(s1.equals(s2));\r\n<\/code><\/pre>\n<p>A. \u5618\u3067\u3059\u3002(Uso desu.)<br \/>\nB. \u771f\u5b9f\u3067\u3059\u3002(Shinjitsu desu.)<br \/>\nC. \u5b9f\u884c\u6642\u306eClassCastException\u3067\u3059\u3002(Jikkouji no ClassCastException desu.)<br \/>\nD. \u30b3\u30f3\u30d1\u30a4\u30eb\u6642\u30a8\u30e9\u30fc\u3067\u3059\u3002(Konpaairu-ji error desu.)<\/p>\n<details>\u7b54\u3048\u3092\u8868\u793a\u3059\u308b\u305f\u3081\u306b\u30af\u30ea\u30c3\u30af\u3057\u3066\u304f\u3060\u3055\u3044<br \/>\n\u6b63\u3057\u3044\u7b54\u3048\uff1aA<br \/>\ns2\u304cString\u578b\u3067\u306f\u306a\u3044\u305f\u3081\u3001false\u304c\u8868\u793a\u3055\u308c\u307e\u3059\u3002String\u306eequals()\u30e1\u30bd\u30c3\u30c9\u306e\u5b9f\u88c5\u3092\u898b\u308b\u3068\u3001\u6e21\u3055\u308c\u305f\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u578b\u304cString\u3067\u3042\u308b\u304b\u3069\u3046\u304b\u3092\u78ba\u8a8d\u3059\u308b\u305f\u3081\u306b\u3001instanceof\u6f14\u7b97\u5b50\u3092\u4f7f\u7528\u3057\u3066\u30c1\u30a7\u30c3\u30af\u304c\u884c\u308f\u308c\u307e\u3059\u3002\u305d\u3046\u3067\u306a\u3044\u5834\u5408\u306f\u3001false\u3092\u8fd4\u3057\u307e\u3059\u3002<\/details>\n<h4>18. \u4ee5\u4e0b\u306e\u30b3\u30fc\u30c9\u30b9\u30cb\u30da\u30c3\u30c8\u306e\u51fa\u529b\u306f\u4f55\u306b\u306a\u308a\u307e\u3059\u304b\uff1f<\/h4>\n<pre class=\"post-pre\"><code>String s1 = \"abc\";\r\nString s2 = new String(\"abc\");\r\ns2.intern();\r\nSystem.out.println(s1 == s2);\r\n<\/code><\/pre>\n<p>A. \u5618(\u3046\u305d)<br \/>\nB. \u771f\u5b9f(\u3057\u3093\u3058\u3064)<br \/>\nC. \u30cc\u30eb<\/p>\n<details>\u7b54\u3048\u3092\u8868\u793a\u3059\u308b\u306b\u306f\u30af\u30ea\u30c3\u30af\u3057\u3066\u304f\u3060\u3055\u3044<br \/>\n\u6b63\u3057\u3044\u7b54\u3048\uff1aA<br \/>\n\u3053\u308c\u306f\u96e3\u3057\u3044\u554f\u984c\u3067\u3042\u308a\u3001\u51fa\u529b\u306ffalse\u306b\u306a\u308a\u307e\u3059\u3002intern()\u30e1\u30bd\u30c3\u30c9\u306f\u6587\u5b57\u5217\u30d7\u30fc\u30eb\u304b\u3089String\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u53c2\u7167\u3092\u8fd4\u3059\u3053\u3068\u304c\u308f\u304b\u3063\u3066\u3044\u307e\u3059\u304c\u3001s2\u306b\u518d\u4ee3\u5165\u3057\u306a\u304b\u3063\u305f\u305f\u3081\u3001s2\u306b\u306f\u5909\u5316\u304c\u3042\u308a\u307e\u305b\u3093\u3002\u3057\u305f\u304c\u3063\u3066\u3001s1\u3068s2\u306f\u7570\u306a\u308b\u53c2\u7167\u3092\u6301\u3063\u3066\u3044\u307e\u3059\u3002<br \/>\n\u884c3\u306e\u30b3\u30fc\u30c9\u3092s2 = s2.intern();\u306b\u5909\u66f4\u3059\u308b\u3068\u3001\u51fa\u529b\u306ftrue\u306b\u306a\u308a\u307e\u3059\u3002<\/details>\n<h4>19. String\u30af\u30e9\u30b9\u3092\u62e1\u5f35\u3057\u3066\u3044\u308b\u5168\u3066\u306e\u30af\u30e9\u30b9\u3092\u9078\u629e\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/h4>\n<p>A. \u6587\u5b57\u5217\u30d0\u30c3\u30d5\u30a1<br \/>\nB. \u6587\u5b57\u5217\u30d3\u30eb\u30c0\u30fc<br \/>\nC. \u6587\u5b57\u5217\u30e9\u30a4\u30bf\u30fc<br \/>\nD. \u5b58\u5728\u3057\u306a\u3044<\/p>\n<details>\u56de\u7b54\u3092\u8868\u793a\u3059\u308b\u306b\u306f\u3001\u30af\u30ea\u30c3\u30af\u3057\u3066\u304f\u3060\u3055\u3044\u3002<br \/>\n\u56de\u7b54\uff1aD<br \/>\n\u305d\u308c\u306f\u5384\u4ecb\u306a\u8cea\u554f\u3067\u3059\u3002String\u306f\u6700\u7d42\u30af\u30e9\u30b9\u306a\u306e\u3067\u3001\u305d\u308c\u3092\u62e1\u5f35\u3059\u308b\u3053\u3068\u306f\u3067\u304d\u307e\u305b\u3093\u3002<\/details>\n<h4>\uff12\uff10\uff0e\u6b21\u306e\u6587\u306e\u3046\u3061\u3001Java\u306eString\u306b\u95a2\u3059\u308b\u771f\u5b9f\u306f\u3069\u308c\u3067\u3059\u304b\uff1f<\/h4>\n<p>A. StringBuffer\u3068\u540c\u69d8\u306b\u3001String\u30af\u30e9\u30b9\u3092\u62e1\u5f35\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<br \/>\nB. java.util\u30d1\u30c3\u30b1\u30fc\u30b8\u306b\u306fString\u30af\u30e9\u30b9\u304c\u5b9a\u7fa9\u3055\u308c\u3066\u3044\u307e\u3059\u3002<br \/>\nC. Java\u3067\u306fString\u306f\u5909\u66f4\u4e0d\u53ef\u3067\u3059\u3002<br \/>\nD. Java\u3067\u306fString\u306f\u30b9\u30ec\u30c3\u30c9\u30bb\u30fc\u30d5\u3067\u3059\u3002<br \/>\nE. Java\u3067\u306fString\u306f\u5927\u6587\u5b57\u3068\u5c0f\u6587\u5b57\u3092\u533a\u5225\u3057\u307e\u3059\u3002<\/p>\n<details>\u7b54\u3048\u3092\u8868\u793a\u3059\u308b\u306b\u306f\u30af\u30ea\u30c3\u30af\u3057\u3066\u304f\u3060\u3055\u3044\u3002<br \/>\n\u6b63\u3057\u3044\u7b54\u3048\uff1aC\u3001D\u3001E<br \/>\nString\u30af\u30e9\u30b9\u306ffinal\u306a\u306e\u3067\u62e1\u5f35\u3067\u304d\u307e\u305b\u3093\u3002StringBuffer\u306f\u305d\u308c\u3092\u62e1\u5f35\u3057\u3066\u3044\u307e\u305b\u3093\u3002String\u30af\u30e9\u30b9\u306fjava.lang\u30d1\u30c3\u30b1\u30fc\u30b8\u306b\u5b9a\u7fa9\u3055\u308c\u3066\u3044\u307e\u3059\u3002\u6587\u5b57\u5217\u306f\u4e0d\u5909\u3067\u3042\u308a\u3001\u3057\u305f\u304c\u3063\u3066Java\u3067\u306f\u30b9\u30ec\u30c3\u30c9\u30bb\u30fc\u30d5\u3067\u3059\u3002String\u306f\u5927\u6587\u5b57\u3068\u5c0f\u6587\u5b57\u3092\u533a\u5225\u3059\u308b\u305f\u3081\u3001\u300cabc\u300d\u3068\u300cABC\u300d\u306f\u7b49\u3057\u304f\u3042\u308a\u307e\u305b\u3093\u3002<\/details>\n<h4>21. \u4e0b\u8a18\u306e\u6587\u306e\u51fa\u529b\u306f\u4f55\u306b\u306a\u308a\u307e\u3059\u304b\uff1f(K\u014dkio no bun no shutsuryoku wa nan ni narimasu ka?)<\/h4>\n<pre class=\"post-pre\"><code>String s1 = null;\r\nSystem.out.print(s1); \/\/ line 2\r\nSystem.out.print(s1.toString()); \/\/ line 3\r\n<\/code><\/pre>\n<p>\u4ee5\u4e0b\u306e\u6587\u3092\u65e5\u672c\u8a9e\u3067\u81ea\u7136\u306b\u8a00\u3044\u63db\u3048\u307e\u3059\u30021\u3064\u306e\u30aa\u30d7\u30b7\u30e7\u30f3\u306e\u307f\u63d0\u4f9b\u3057\u307e\u3059\uff1a<\/p>\n<p>A. nullnull<br \/>\nB. null\u306e\u5f8c\u306bNullPointerException<br \/>\nC. NullPointerException<\/p>\n<p>A. \u30cc\u30eb\u30cc\u30eb<br \/>\nB. \u30cc\u30eb\u306e\u5f8c\u306b\u30cc\u30eb\u30dd\u30a4\u30f3\u30bf\u4f8b\u5916<br \/>\nC. \u30cc\u30eb\u30dd\u30a4\u30f3\u30bf\u4f8b\u5916<\/p>\n<details>\u4ee5\u4e0b\u3092\u65e5\u672c\u8a9e\u3067\u81ea\u7136\u306b\u8a00\u3044\u63db\u3048\u307e\u3059\u30021\u3064\u306e\u30aa\u30d7\u30b7\u30e7\u30f3\u306e\u307f\u304c\u5fc5\u8981\u3067\u3059\u3002\u56de\u7b54\u3092\u8868\u793a\u3059\u308b\u306b\u306f\u30af\u30ea\u30c3\u30af\u3057\u3066\u304f\u3060\u3055\u3044<br \/>\n\u6b63\u89e3\uff1aB<br \/>\n2\u884c\u76ee\u306f\u3001\u6b21\u306e\u3088\u3046\u306bnull\u306e\u78ba\u8a8d\u304c\u884c\u308f\u308c\u308b\u305f\u3081\u3001null\u304c\u8868\u793a\u3055\u308c\u307e\u3059\u3002<br \/>\nif (s == null) { s = &#8220;null&#8221;;}<br \/>\n3\u884c\u76ee\u306f\u3001null\u4e0a\u3067toString()\u95a2\u6570\u3092\u547c\u3073\u51fa\u305d\u3046\u3068\u3057\u3066\u3044\u308b\u305f\u3081\u3001NullPointerException\u304c\u30b9\u30ed\u30fc\u3055\u308c\u307e\u3059\u3002<\/p>\n<\/details>\n<h2>\u7d50\u8ad6<\/h2>\n<p>\u3053\u306e\u30af\u30a4\u30ba\u3067\u306f\u3001String\u306b\u95a2\u3059\u308b\u91cd\u8981\u306a\u30dd\u30a4\u30f3\u30c8\u3092\u307b\u307c\u7db2\u7f85\u3057\u3088\u3046\u3068\u3057\u307e\u3057\u305f\u3002\u3082\u3057\u8208\u5473\u6df1\u3044\u6982\u5ff5\u304c\u898b\u843d\u3068\u3055\u308c\u3066\u3044\u308b\u3068\u601d\u308f\u308c\u308b\u5834\u5408\u306f\u3001\u30b3\u30e1\u30f3\u30c8\u3092\u901a\u3058\u3066\u304a\u77e5\u3089\u305b\u304f\u3060\u3055\u3044\u3002\u3082\u3057\u30af\u30a4\u30ba\u304c\u6c17\u306b\u5165\u3063\u305f\u5834\u5408\u306f\u3001\u4ed6\u306e\u4eba\u3068\u3082\u5171\u6709\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Java String Quiz\u3078\u3088\u3046\u3053\u305d\u3002String\u306fJava\u3067\u6700\u3082\u91cd\u8981\u306a\u30af\u30e9\u30b9\u306e\u4e00\u3064\u3067\u3059\u3002\u3082\u3057Java\u3067\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u3092\u4f55\u304b\u3057\u3089\u884c\u3063\u305f\u3053\u3068\u304c\u3042\u308c\u3070\u3001\u5fc5\u305a\u4f7f\u7528\u3057\u305f\u3053\u3068\u304c\u3042\u308b\u3067\u3057\u3087\u3046\u3002 Java\u306e\u9762\u63a5\u3084\u30af\u30a4\u30ba\u306e\u554f\u984c\u3068\u3057 [&hellip;]<\/p>\n","protected":false},"author":11,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[26,61],"class_list":["post-913","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-26","tag-61"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v21.5 (Yoast SEO v21.5) - 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