{"id":2285,"date":"2016-12-21T03:36:58","date_gmt":"2016-12-20T18:36:58","guid":{"rendered":"http:\/\/yucchi.jp\/blog\/?p=2285"},"modified":"2016-12-22T23:40:52","modified_gmt":"2016-12-22T14:40:52","slug":"java-puzzlers-advent-calendar-2016%e3%80%80-coffee-break","status":"publish","type":"post","link":"http:\/\/yucchi.jp\/blog\/?p=2285","title":{"rendered":"Java Puzzlers Advent Calendar 2016\u3000– Coffee Break —"},"content":{"rendered":"

\u3053\u306e\u30a8\u30f3\u30c8\u30ea\u30fc\u306f http:\/\/qiita.com\/advent-calendar\/2016\/java_puzzlers<\/a> \u306e 21 \u65e5\u76ee\u3067\u3059\u3002<\/p>\n

\u6628\u65e5\u306f @zr_tex8r<\/a> \u3055\u3093\u306e\u306e\u300c\u30eb\u30fc\u30d7\u4ee5\u5916\u306e\u6587\u306b\u30e9\u30d9\u30eb\u306f\u4ed8\u3051\u3089\u308c\u308b\u304b\uff1f<\/a>\u300d\u3067\u3057\u305f\u3002<\/p>\n

\u660e\u65e5\u306f @khasunuma<\/a> \u3055\u3093\u306e\u300c\u8ab0\u3082\u6295\u7a3f\u3057\u305d\u3046\u306b\u306a\u3044\u306e\u3067\u3001\u3082\u3046\u5c11\u3057\u9811\u5f35\u3063\u3066\u307f\u308b\u300d\u3067\u3059\u3002<\/p>\n

\u9023\u65e5\u9ad8\u5ea6\u306a Java Puzzle \u304c\u6295\u7a3f\u3055\u308c\u3066\u3044\u3066\u697d\u3057\u307e\u305b\u3066\u3044\u305f\u3060\u3044\u3066\u307e\u3059\u3002<\/p>\n

\u300c\u30b8\u30e3\u30d0\u30c1\u30e7\u30c3\u30c8\u30c7\u30ad\u30eb\u300d<\/strong>\u3068\u3044\u3046\u51c4\u3044\u4eba\u305f\u3061\u306e\u6295\u7a3f\u3067\u30af\u30ea\u30c6\u30a3\u30ab\u30eb\u30d2\u30c3\u30c8\u3092\u98df\u3089\u3063\u3066\u30c0\u30a6\u30f3\u3057\u3066\u307e\u3059\u3002(^_^;<\/p>\n

\u3053\u3053\u3089\u3078\u3093\u3067 CoffeeBreak \u3068\u3044\u3046\u3053\u3068\u3067\u606f\u629c\u304d\u30d1\u30ba\u30eb\u3067\u30a8\u30f3\u30c8\u30ea\u30fc\u3055\u305b\u3066\u3044\u305f\u3060\u304d\u307e\u3059\u3002<\/p>\n

\u53e4\u5178\u7684\u306a\u3042\u308a\u3075\u308c\u305f\u30cd\u30bf\u3067\u3059\u304c\u304a\u697d\u3057\u307f\u304f\u3060\u3055\u3044\u3002<\/p>\n

\u3061\u306a\u307f\u306b\u3053\u306e\u30d7\u30ed\u30b0\u30e9\u30e0\u306f\u30d1\u30ba\u30eb\u7528\u306a\u306e\u3067\u5b9f\u7528\u6027\u306e\u6b20\u7247\u3082\u3042\u308a\u307e\u305b\u3093\u3002<\/p>\n

\u554f\u984c<\/h4>\n

\u6b21\u306e\u30d7\u30ed\u30b0\u30e9\u30e0\u3092\u30b3\u30f3\u30d1\u30a4\u30eb\u3001\u5b9f\u884c\u3059\u308b\u3068\u6a19\u6e96\u51fa\u529b\u306b\u3069\u3093\u306a\u7d50\u679c\u3092\u8868\u793a\u3059\u308b\u3067\u3057\u3087\u3046\u304b\uff1f<\/p>\n

package jp.yucchi.lookbeforeyouleap;\r\n\r\nimport java.lang.management.ManagementFactory;\r\nimport java.util.ArrayList;\r\nimport java.util.List;\r\nimport java.util.concurrent.CompletableFuture;\r\nimport java.util.concurrent.ExecutorService;\r\nimport java.util.concurrent.Executors;\r\n\r\npublic class LookBeforeYouLeap {\r\n\r\n    public static void main(String[] args) {\r\n\r\n        Runnable r = new Friends();\r\n\r\n        int procs = ManagementFactory.getOperatingSystemMXBean().getAvailableProcessors();\r\n        if (procs < 2) {\r\n            procs = 1;\r\n        }\r\n        ExecutorService executor = Executors.newFixedThreadPool(procs);\r\n\r\n        CompletableFuture<Void> friends1e = CompletableFuture.runAsync(r, executor);\r\n        CompletableFuture<Void> friends2e = CompletableFuture.runAsync(r, executor);\r\n        CompletableFuture<Void> friends3e = CompletableFuture.runAsync(r, executor);\r\n        CompletableFuture<Void> friends4e = CompletableFuture.runAsync(r, executor);\r\n\r\n        CompletableFuture<Void> friends1 = CompletableFuture.runAsync(r);\r\n        CompletableFuture<Void> friends2 = CompletableFuture.runAsync(r);\r\n        CompletableFuture<Void> friends3 = CompletableFuture.runAsync(r);\r\n        CompletableFuture<Void> friends4 = CompletableFuture.runAsync(r);\r\n        CompletableFuture<Void> allTask = CompletableFuture.allOf(friends1, friends2, friends3, friends4, friends1e, friends2e, friends3e, friends4e);\r\n\r\n        allTask.join();\r\n\r\n        while (!executor.isShutdown()) {\r\n            executor.shutdown();\r\n        }\r\n\r\n        System.out.println(\"executor.shutdown()\");\r\n    }\r\n\r\n    private static class Friends implements Runnable {\r\n\r\n        private final List<String> friends = new ArrayList<>(16);\r\n\r\n        public synchronized void add(String name) {\r\n            friends.add(name);\r\n        }\r\n\r\n        public synchronized void remove(String name) {\r\n            friends.remove(name);\r\n        }\r\n\r\n        public void update() {\r\n            friends.add(\"\u5317\u5ddd\u666f\u5b50\");\r\n            friends.add(\"\u525b\u529b\u5f69\u82bd\");\r\n            friends.add(\"\u6850\u8c37\u7f8e\u73b2\");\r\n            friends.add(\"\u5800\u5317\u771f\u5e0c\");\r\n            friends.add(\"\u65b0\u57a3\u7d50\u8863\");\r\n            friends.remove(\"\u5317\u5ddd\u666f\u5b50\");\r\n            friends.remove(\"\u525b\u529b\u5f69\u82bd\");\r\n            friends.remove(\"\u6850\u8c37\u7f8e\u73b2\");\r\n            friends.remove(\"\u5800\u5317\u771f\u5e0c\");\r\n\r\n            System.out.println(friends.hashCode() + \" \" + Thread.currentThread().getName());\r\n        }\r\n\r\n        @Override\r\n        public void run() {\r\n            update();\r\n        }\r\n\r\n    }\r\n\r\n}\r\n\r\n<\/pre>\n
(1)<\/strong> <\/p>\n
1767504129 pool-1-thread-1
1767504129 pool-1-thread-3
1767504129 pool-1-thread-2
1767504129 pool-1-thread-4
-243838107 ForkJoinPool.commonPool-worker-25
1829062017 ForkJoinPool.commonPool-worker-18
1664456421 ForkJoinPool.commonPool-worker-18
856650241 ForkJoinPool.commonPool-worker-25
executor.shutdown()<\/p>\n
ExecutorService \u3092\u4f7f\u3063\u305f\u65b9\u306f\u540c\u3058\u30cf\u30c3\u30b7\u30e5\u30fb\u30b3\u30fc\u30c9\u5024\u3092\u5fc5\u305a\u8fd4\u3059\u3002<\/p>\n
(2)<\/strong><\/p>\n
1767504129 pool-1-thread-4
1767504129 pool-1-thread-2
1767504129 pool-1-thread-1
1767504129 pool-1-thread-3
1829062017 ForkJoinPool.commonPool-worker-25
1829062017 ForkJoinPool.commonPool-worker-18
1829062017 ForkJoinPool.commonPool-worker-18
1829062017 ForkJoinPool.commonPool-worker-25
executor.shutdown()<\/p>\n
ExecutorService\u3001ForkJoin \u3068\u3082\u306b\u540c\u3058\u30cf\u30c3\u30b7\u30e5\u30fb\u30b3\u30fc\u30c9\u5024\u3092\u5fc5\u305a\u8fd4\u3059\u3002<\/p>\n
(3)<\/strong><\/p>\n
-230323071 pool-1-thread-1
1767504129 pool-1-thread-4
-2046939163 pool-1-thread-3
-230323071 pool-1-thread-2
-243838107 ForkJoinPool.commonPool-worker-25
1829062017 ForkJoinPool.commonPool-worker-18
1664456421 ForkJoinPool.commonPool-worker-18
856650241 ForkJoinPool.commonPool-worker-25
executor.shutdown()<\/p>\n
\u540c\u3058\u30cf\u30c3\u30b7\u30e5\u30fb\u30b3\u30fc\u30c9\u5024\u3092\u8fd4\u3059\u5834\u5408\u3082\u3042\u308b<\/p>\n
(4)<\/strong><\/p>\n
1647295788 pool-1-thread-1
-591109637 pool-1-thread-4
1767504129 pool-1-thread-2
357637727 pool-1-thread-3
-243838107 ForkJoinPool.commonPool-worker-25
1829062017 ForkJoinPool.commonPool-worker-18
1664456421 ForkJoinPool.commonPool-worker-18
856650241 ForkJoinPool.commonPool-worker-25
executor.shutdown()<\/p>\n
\u304a\u306e\u304a\u306e\u30e6\u30cb\u30fc\u30af\u306a\u30cf\u30c3\u30b7\u30e5\u30fb\u30b3\u30fc\u30c9\u5024\u3092\u8fd4\u3059\u3002<\/p>\n
(5)<\/strong><\/p>\n
\u5b9f\u884c\u6642\u4f8b\u5916<\/p>\n
(6)<\/strong><\/p>\n
\u30b3\u30f3\u30d1\u30a4\u30eb\u30a8\u30e9\u30fc<\/p>\n
 <\/p>\n
\u7b54\u3048<\/h4>\n
\u6b63\u89e3\u306f\u2025\u2025<\/p>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
(1)<\/strong> \u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002<\/p>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
(2)  <\/strong>\u3067\u3082\u3042\u308a\u307e\u305b\u3093\u3002<\/p>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
(3) <\/strong>\u304c\u6b63\u89e3\u3068\u3044\u3044\u305f\u3044\u3068\u3053\u308d\u3067\u3059\u304c\u9055\u3044\u307e\u3059\u3002<\/p>\n
\u5b9f\u306f\u3053\u306e\u3088\u3046\u306b\u51fa\u529b\u3055\u308c\u308b\u3053\u3068\u3082\u3042\u308a\u307e\u3059\u3002<\/p>\n
\u305f\u3060\u3057\u3001100 \u30d1\u30fc\u30bb\u30f3\u30c8\u3053\u306e\u3088\u3046\u306b\u51fa\u529b\u3055\u308c\u308b\u4fdd\u8a3c\u306f\u306a\u304f\u30d7\u30ed\u30b0\u30e9\u30e0\u306e\u30b3\u30fc\u30c9\u306b\u306f\u81f4\u547d\u7684\u306a\u5927\u304d\u306a\u554f\u984c\u304c\u3072\u305d\u3093\u3067\u3044\u307e\u3059\u3002<\/p>\n
\u3088\u3063\u3066\u3001\u4e0d\u6b63\u89e3\u3068\u3044\u3046\u3053\u3068\u3067\u3054\u4e86\u627f\u304f\u3060\u3055\u3044\u307e\u305b\u3002<\/p>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
\u6b63\u89e3\u306f (5) \u5b9f\u884c\u6642\u4f8b\u5916\u3067\u3059\u3002<\/font><\/strong><\/p>\n
java.util.ConcurrentModificationException \u304c\u6295\u3052\u3089\u308c\u307e\u3059\u3002<\/p>\n
65 \u884c\u76ee\u306e System.out.println(friends.hashCode() + ” ” + Thread.currentThread().getName()); \u304c\u539f\u56e0\u3067\u3059\u3002<\/p>\n
java.util.ConcurrentModificationException \u3068\u306f\u3069\u3093\u306a\u4f8b\u5916\u306a\u306e\u3067\u3057\u3087\u3046\u304b\uff1f<\/p>\n
Javadoc<\/a> \u3092\u898b\u3066\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\n
\u3053\u306e\u4f8b\u5916\u306f\u3001\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u4e26\u884c\u5909\u66f4\u3092\u691c\u51fa\u3057\u305f\u30e1\u30bd\u30c3\u30c9\u306b\u3088\u3063\u3066\u3001\u305d\u306e\u3088\u3046\u306a\u5909\u66f4\u304c\u8a31\u53ef\u3055\u308c\u3066\u3044\u306a\u3044\u5834\u5408\u306b\u30b9\u30ed\u30fc\u3055\u308c\u307e\u3059\u3002
 
\u305f\u3068\u3048\u3070\u3001\u3042\u308b\u30b9\u30ec\u30c3\u30c9\u304c Collection \u3067\u7e70\u308a\u8fd4\u3057\u51e6\u7406\u3092\u884c\u306a\u3063\u3066\u3044\u308b\u9593\u306b\u3001\u5225\u306e\u30b9\u30ec\u30c3\u30c9\u304c\u305d\u306e Collection \u3092\u5909\u66f4\u3059\u308b\u3053\u3068\u306f\u4e00\u822c\u306b\u8a31\u53ef\u3055\u308c\u307e\u305b\u3093\u3002<\/font><\/p>\n
\u901a\u5e38\u3001\u305d\u306e\u3088\u3046\u306a\u74b0\u5883\u3067\u306f\u3001\u7e70\u308a\u8fd4\u3057\u51e6\u7406\u306e\u7d50\u679c\u306f\u4fdd\u8a3c\u3055\u308c\u307e\u305b\u3093\u3002<\/font><\/p>\n
\u3044\u304f\u3064\u304b\u306e\u30a4\u30c6\u30ec\u30fc\u30bf (Iterator) \u306e\u5b9f\u88c5 (JRE \u304c\u63d0\u4f9b\u3059\u308b\u3059\u3079\u3066\u306e\u4e00\u822c\u7684\u306a\u76ee\u7684\u306e\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u306e\u5b9f\u88c5\u306e\u3001\u30a4\u30c6\u30ec\u30fc\u30bf\u306e\u5b9f\u88c5\u3092\u542b\u3080) \u306f\u3001\u305d\u306e\u52d5\u4f5c\u304c\u691c\u51fa\u3055\u308c\u305f\u5834\u5408\u306b\u3053\u306e\u4f8b\u5916\u3092\u30b9\u30ed\u30fc\u3059\u308b\u3053\u3068\u3092\u9078\u629e\u3067\u304d\u307e\u3059\u3002<\/font><\/p>\n
\u3053\u306e\u4f8b\u5916\u3092\u30b9\u30ed\u30fc\u3059\u308b\u30a4\u30c6\u30ec\u30fc\u30bf\u306f\u3001\u30d5\u30a7\u30a4\u30eb\u30d5\u30a1\u30b9\u30c8\u30a4\u30c6\u30ec\u30fc\u30bf\u3068\u547c\u3070\u308c\u307e\u3059\u3002<\/font><\/p>\n
\u30a4\u30c6\u30ec\u30fc\u30bf\u306f\u3001\u5c06\u6765\u306e\u4e88\u6e2c\u3067\u304d\u306a\u3044\u6642\u70b9\u306b\u304a\u3044\u3066\u4e88\u6e2c\u3067\u304d\u306a\u3044\u52d5\u4f5c\u304c\u767a\u751f\u3059\u308b\u5371\u967a\u3092\u56de\u907f\u3059\u308b\u305f\u3081\u306b\u3001\u305f\u3060\u3061\u306b\u304b\u3064\u624b\u969b\u3088\u304f\u4f8b\u5916\u3092\u30b9\u30ed\u30fc\u3057\u307e\u3059\u3002 <\/font><\/p>\n
\u3053\u306e\u4f8b\u5916\u306f\u3001\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u304c\u5225\u306e\u30b9\u30ec\u30c3\u30c9\u306b\u3088\u3063\u3066\u4e26\u884c\u3057\u3066\u66f4\u65b0\u3055\u308c\u3066\u3044\u306a\u3044\u3053\u3068\u3092\u5fc5\u305a\u3057\u3082\u793a\u3057\u3066\u3044\u308b\u308f\u3051\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002<\/font><\/p>\n
\u5358\u4e00\u306e\u30b9\u30ec\u30c3\u30c9\u304c\u3001\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u898f\u7d04\u306b\u9055\u53cd\u3059\u308b\u4e00\u9023\u306e\u30e1\u30bd\u30c3\u30c9\u3092\u767a\u884c\u3057\u305f\u5834\u5408\u3001\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306f\u3053\u306e\u4f8b\u5916\u3092\u30b9\u30ed\u30fc\u3057\u307e\u3059\u3002<\/font><\/p>\n
\u305f\u3068\u3048\u3070\u3001\u30d5\u30a7\u30a4\u30eb\u30d5\u30a1\u30b9\u30c8\u30a4\u30c6\u30ec\u30fc\u30bf\u3092\u6301\u3064\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u306e\u7e70\u308a\u8fd4\u3057\u51e6\u7406\u3092\u884c\u3044\u306a\u304c\u3089\u3001\u30b9\u30ec\u30c3\u30c9\u304c\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u3092\u76f4\u63a5\u4fee\u6b63\u3059\u308b\u5834\u5408\u3001\u30a4\u30c6\u30ec\u30fc\u30bf\u306f\u3053\u306e\u4f8b\u5916\u3092\u30b9\u30ed\u30fc\u3057\u307e\u3059\u3002 <\/font><\/p>\n
\u901a\u5e38\u3001\u975e\u540c\u671f\u306e\u4e26\u884c\u5909\u66f4\u304c\u3042\u308b\u5834\u5408\u3001\u78ba\u304b\u306a\u4fdd\u8a3c\u3092\u884c\u3046\u3053\u3068\u306f\u4e0d\u53ef\u80fd\u306a\u306e\u3067\u3001\u30d5\u30a7\u30a4\u30eb\u30d5\u30a1\u30b9\u30c8\u306e\u52d5\u4f5c\u3092\u4fdd\u8a3c\u3059\u308b\u3053\u3068\u306f\u3067\u304d\u307e\u305b\u3093\u3002<\/font><\/p>\n
\u30d5\u30a7\u30a4\u30eb\u30d5\u30a1\u30b9\u30c8\u30aa\u30da\u30ec\u30fc\u30b7\u30e7\u30f3\u306f\u6700\u5584\u52aa\u529b\u539f\u5247\u306b\u57fa\u3065\u304d\u3001ConcurrentModificationException \u3092\u30b9\u30ed\u30fc\u3057\u307e\u3059\u3002<\/font><\/p>\n
\u3057\u305f\u304c\u3063\u3066\u3001\u6b63\u78ba\u3092\u671f\u3059\u305f\u3081\u306b\u3053\u306e\u4f8b\u5916\u306b\u4f9d\u5b58\u3059\u308b\u30d7\u30ed\u30b0\u30e9\u30e0\u3092\u66f8\u304f\u3053\u3068\u306f\u8aa4\u308a\u3067\u3059\u3002<\/font><\/p>\n
ConcurrentModificationException \u306f\u3001\u30d0\u30b0\u3092\u691c\u51fa\u3059\u308b\u305f\u3081\u306b\u306e\u307f\u4f7f\u7528\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/font><\/p>\n
\u4ee5\u4e0a\u3001 Javadoc<\/a> \u3088\u308a<\/p>\n
\u3064\u307e\u308a\u3001 Java \u306e\u540c\u671f\u5316\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u306f\u30de\u30eb\u30c1\u30b9\u30ec\u30c3\u30c9\u306a\u3069\u306b\u3088\u308b\u4e26\u884c\u7684\u306a\u5909\u66f4\u306b\u306f\u5b8c\u5168\u306b\u5bfe\u5fdc\u3067\u304d\u306a\u3044\u3068\u3044\u3046\u3053\u3068\u3067\u3059\u3002<\/p>\n
\u3060\u304b\u3089\u4e26\u884c\u7684\u306a\u5909\u66f4\u3078\u306e\u5bfe\u51e6\u306f\u30a4\u30c6\u30ec\u30fc\u30b7\u30e7\u30f3\u958b\u59cb\u5f8c\u306b Collection \u304c\u5909\u66f4\u3055\u308c\u305f\u306e\u3092\u691c\u51fa\u3059\u308b\u3068 ConcurrentModificationException \u4f8b\u5916\u3092\u305f\u3060\u3061\u306b\u6295\u3052\u308b\u3068\u3044\u3046\u30d5\u30a7\u30a4\u30eb\u30d5\u30a1\u30b9\u30c8\u3068\u3044\u3046\u8a2d\u8a08\u306b\u306a\u3063\u3066\u3044\u308b\u3002<\/p>\n
\u305f\u3060\u3057\u3001\u3053\u306e\u30d5\u30a7\u30a4\u30eb\u30d5\u30a1\u30b9\u30c8\u8a2d\u8a08\u306f\u5b9f\u884c\u6027\u80fd\u306b\u4e0e\u3048\u308b\u5f71\u97ff\u3092\u6291\u3048\u308b\u305f\u3081\u306b\u305d\u308c\u307b\u3069\u512a\u79c0\u306a\u8a2d\u8a08\u306b\u306f\u306a\u3063\u3066\u306a\u3044\u3088\u3046\u3067\u3059\u3002<\/p>\n
\u3067\u306f\u3001\u3053\u306e\u554f\u984c\u306e\u9375\u306f\u3069\u3053\u306b\u3042\u308b\u306e\u3060\u308d\u3046\uff1f<\/p>\n
\u3069\u3046\u3057\u3066\uff1f Iterator \u3067\u56de\u3057\u3066\u306a\u3044\u306e\u306b\u3068\u601d\u308f\u308c\u308b\u4eba\u306f\u7d14\u306a\u5fc3\u306e\u6301\u3061\u4e3b\u3067\u3057\u3087\u3046\u3002<\/p>\n
hashCode() \u30e1\u30bd\u30c3\u30c9\u306e\u5b9f\u88c5\u306f\u6b21\u306e\u3088\u3046\u306b\u306a\u3063\u3066\u3044\u307e\u3059\u3002<\/p>\n
    public int hashCode() {\r\n        int hashCode = 1;\r\n        for (E e : this)\r\n            hashCode = 31*hashCode + (e==null ? 0 : e.hashCode());\r\n        return hashCode;\r\n    }\r\n<\/pre>\n
\u62e1\u5f35 for \u6587\u3092\u4f7f\u3063\u3066\u3044\u307e\u3059\u306d\u3002<\/strong><\/font><\/p>\n
\u3053\u308c\u306f\u5185\u90e8\u3067\u30a4\u30c6\u30ec\u30fc\u30bf\u3092\u4f7f\u3063\u3066\u307e\u3059\u3002\u3060\u304b\u3089 java.util.ConcurrentModificationException \u304c\u6295\u3052\u3089\u308c\u307e\u3059\u3002<\/p>\n
\u3082\u3046\u5c11\u3057\u78ba\u8a8d\u3059\u308b\u305f\u3081\u306b\u6b21\u306e\u3088\u3046\u306a\u5909\u66f4\u3092\u30d7\u30ed\u30b0\u30e9\u30e0\u306b\u52a0\u3048\u3066\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\n
65 \u884c\u76ee\u306e System.out.println(friends.hashCode() + ” ” + Thread.currentThread().getName()); \u3092<\/p>\n
System.out.println(“My Friends: ” + friends + ” ” + Thread.currentThread().getName()); \u306b\u5909\u66f4\u3057\u3066\u5b9f\u884c\u3057\u3066\u307f\u307e\u3059\u3002<\/p>\n
\u3053\u308c\u3067\u3082 java.util.ConcurrentModificationException \u304c\u6295\u3052\u3089\u308c\u307e\u3059\u3002<\/p>\n
\u3069\u3046\u3057\u3066\u3067\u3057\u3087\u3046\uff1f<\/p>\n
\u307e\u305a\u3001\u6587\u5b57\u5217\u306e\u9023\u7d50\u64cd\u4f5c\u306b\u3088\u308a StringBuilder \u30af\u30e9\u30b9\u306e\u6b21\u306e\u30e1\u30bd\u30c3\u30c9\u304c\u547c\u3070\u308c\u307e\u3059\u3002<\/p>\n
    @Override\r\n    public StringBuilder append(Object obj) {\r\n        return append(String.valueOf(obj));\r\n    }\r\n<\/pre>\n
\u7d9a\u3044\u3066 String \u30af\u30e9\u30b9\u306e\u6b21\u306e\u30e1\u30bd\u30c3\u30c9\u304c\u547c\u3070\u308c\u307e\u3059\u3002<\/p>\n
    public static String valueOf(Object obj) {\r\n        return (obj == null) ? \"null\" : obj.toString();\r\n    }\r\n<\/pre>\n
\u305d\u3057\u3066\u3001AbstractCollection<E> \u30af\u30e9\u30b9\u306e\u6b21\u306e\u30e1\u30bd\u30c3\u30c9\u304c\u5b9f\u884c\u3055\u308c\u307e\u3059\u3002<\/p>\n
    public String toString() {\r\n        Iterator<E> it = iterator();\r\n        if (! it.hasNext())\r\n            return \"[]\";\r\n\r\n        StringBuilder sb = new StringBuilder();\r\n        sb.append('[');\r\n        for (;;) {\r\n            E e = it.next();\r\n            sb.append(e == this ? \"(this Collection)\" : e);\r\n            if (! it.hasNext())\r\n                return sb.append(']').toString();\r\n            sb.append(',').append(' ');\r\n        }\r\n    }\r\n\r\n}\r\n<\/pre>\n
\u304a\u304a\u3063\uff01\u3000Iterator \u3067\u3076\u3093\u56de\u3057\u3066\u307e\u3059\u306d<\/strong><\/font>\u3002<\/p>\n
\u554f\u984c\u306e hashCode() \u30e1\u30bd\u30c3\u30c9\u540c\u69d8\u306b\u5185\u90e8\u3067 Iterator \u3092\u4f7f\u3063\u3066\u307e\u3059\u3002<\/p>\n
\u3053\u306e\u3088\u3046\u306b\u9593\u63a5\u7684\u306b Iterator \u3092\u4f7f\u3063\u3066\u3044\u308b\u3053\u3068\u306b\u6c17\u3065\u304b\u305a\u306b\u81f4\u547d\u7684\u306a\u30df\u30b9\u3092\u304a\u304b\u3057\u3066\u3057\u307e\u3046\u53ef\u80fd\u6027\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n
Collection \u306e\u53d6\u308a\u6271\u3044\u306b\u306f\u7d30\u5fc3\u306e\u6ce8\u610f\u304c\u5fc5\u8981\u3067\u3059\u3002<\/p>\n
\u305d\u308c\u3067\u306f\u3053\u306e\u30d7\u30ed\u30b0\u30e9\u30e0\u306e\u4fee\u6b63\u306f\u3069\u3046\u3059\u308c\u3070\u3044\u3044\u3067\u3057\u3087\u3046\u304b\uff1f<\/p>\n
\u3053\u306e\u554f\u984c\u306e\u30d7\u30ed\u30b0\u30e9\u30e0\u306f Collection \u3078\u306e\u8981\u7d20\u306e\u8ffd\u52a0\u3001\u524a\u9664\u3092\u6b21\u306e\u3088\u3046\u306b synchronized \u30e1\u30bd\u30c3\u30c9\u3067\u6392\u4ed6\u5236\u5fa1\u3092\u884c\u3063\u3066\u307e\u3059\u3002<\/p>\n
        public synchronized void add(String name) {\r\n            friends.add(name);\r\n        }\r\n\r\n        public synchronized void remove(String name) {\r\n            friends.remove(name);\r\n        }\r\n<\/pre>\n
\u3053\u308c\u3067\u306f Collection \u3092\u30a4\u30c6\u30ec\u30fc\u30b7\u30e7\u30f3\u3057\u3066\u3044\u308b\u9593\u306b\u5225\u306e\u30b9\u30ec\u30c3\u30c9\u306b\u3088\u308b\u5909\u66f4\u64cd\u4f5c\u304c\u884c\u308f\u308c\u3066\u3057\u307e\u3044\u307e\u3059\u3002<\/p>\n
\u6392\u4ed6\u5236\u5fa1\u3092\u884c\u3046\u306b\u306f public void update() \u30e1\u30bd\u30c3\u30c9\u3092 public synchronized void update() \u30e1\u30bd\u30c3\u30c9\u306b\u5909\u66f4\u3059\u308c\u3070 OK \u3067\u3059\u3002<\/p>\n
\u8981\u7d20\u306e\u8ffd\u52a0\u3001\u524a\u9664\u306e\u30e1\u30bd\u30c3\u30c9\u306f\u6392\u4ed6\u5236\u5fa1\u3092\u884c\u3046\u5fc5\u8981\u306f\u3053\u308c\u3067\u306a\u304f\u306a\u308a\u307e\u3059\u3002<\/p>\n
synchronized \u306b\u3088\u308b\u6392\u4ed6\u5236\u5fa1\u3092\u884c\u3044\u305f\u304f\u306a\u3044\u5834\u5408\u306f ReentrantLock \u3092\u4f7f\u3046\u65b9\u6cd5\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n
        Lock lock = new ReentrantLock();\r\n\r\n        @Override\r\n        public void run() {\r\n            lock.lock();\r\n            try {\r\n                update();\r\n            } finally {\r\n                lock.unlock();\r\n            }\r\n        }\r\n<\/pre>\n
\u6700\u5f8c\u306b CopyOnWriteArrayList<E> \u3092\u4f7f\u3046\u65b9\u6cd5\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n
\u305f\u3060\u3057\u3001\u3053\u308c\u306f\u4eca\u307e\u3067\u306e\u6392\u4ed6\u5236\u5fa1\u3068\u306f\u7570\u306a\u308a\u307e\u3059\u3002<\/p>\n
CopyOnWriteArrayList<E> \u306e Javadoc<\/a> \u3092\u8aad\u3093\u3067\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\n
public class CopyOnWriteArrayList<E> extends Object implements List<E>, RandomAccess, Cloneable, Serializable<\/font><\/p>\n
\u57fa\u306b\u306a\u308b\u914d\u5217\u306e\u65b0\u3057\u3044\u30b3\u30d4\u30fc\u3092\u4f5c\u6210\u3059\u308b\u3053\u3068\u306b\u3088\u308a\u3001\u3059\u3079\u3066\u306e\u63a8\u79fb\u7684\u64cd\u4f5c(add\u3001set\u306a\u3069)\u304c\u5b9f\u88c5\u3055\u308c\u308bArrayList\u306e\u30b9\u30ec\u30c3\u30c9\u30fb\u30bb\u30fc\u30d5\u306a\u5909\u6570\u3067\u3059\u3002
 
\u901a\u5e38\u3001\u3053\u308c\u306f\u975e\u5e38\u306b\u52b9\u7387\u304c\u60aa\u3044\u306e\u3067\u3059\u304c\u3001\u30c8\u30e9\u30d0\u30fc\u30b5\u30eb\u64cd\u4f5c\u304c\u5909\u66f4\u3092\u6570\u306e\u70b9\u3067\u5927\u5e45\u306b\u4e0a\u56de\u308b\u5834\u5408\u306b\u306f\u3001\u4ee3\u66ff\u624b\u6bb5\u3088\u308a\u3082\u52b9\u7387\u304c\u826f\u3044\u5834\u5408\u304c\u3042\u308a\u307e\u3059\u3002<\/font><\/p>\n
\u307e\u305f\u3001\u3053\u308c\u306f\u3001\u30c8\u30e9\u30d0\u30fc\u30b5\u30eb\u3092\u540c\u671f\u3067\u304d\u306a\u3044\u5834\u5408\u3084\u3001\u540c\u671f\u3059\u308b\u3053\u3068\u3092\u671b\u307e\u306a\u3044\u304c\u3001\u4e26\u884c\u30b9\u30ec\u30c3\u30c9\u9593\u306e\u5e72\u6e09\u3092\u6392\u9664\u3059\u308b\u5fc5\u8981\u304c\u3042\u308b\u5834\u5408\u306b\u6709\u7528\u3067\u3059\u3002<\/font><\/p>\n
\u300c\u30b9\u30ca\u30c3\u30d7\u30b7\u30e7\u30c3\u30c8\u300d\u30b9\u30bf\u30a4\u30eb\u306e\u30a4\u30c6\u30ec\u30fc\u30bf\u30fb\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u30a4\u30c6\u30ec\u30fc\u30bf\u306e\u4f5c\u6210\u6642\u70b9\u3067\u306e\u914d\u5217\u72b6\u614b\u3078\u306e\u53c2\u7167\u3092\u4f7f\u7528\u3057\u307e\u3059\u3002<\/font><\/p>\n
\u3053\u306e\u914d\u5217\u304c\u30a4\u30c6\u30ec\u30fc\u30bf\u306e\u6709\u52b9\u671f\u9593\u4e2d\u306b\u5909\u66f4\u3055\u308c\u308b\u3053\u3068\u306f\u6c7a\u3057\u3066\u306a\u3044\u305f\u3081\u3001\u5e72\u6e09\u306f\u4e0d\u53ef\u80fd\u3067\u3042\u308a\u3001\u30a4\u30c6\u30ec\u30fc\u30bf\u306fConcurrentModificationException\u3092\u30b9\u30ed\u30fc\u3057\u306a\u3044\u3053\u3068\u304c\u4fdd\u8a3c\u3055\u308c\u307e\u3059\u3002<\/font><\/p>\n
\u30a4\u30c6\u30ec\u30fc\u30bf\u306f\u3001\u30a4\u30c6\u30ec\u30fc\u30bf\u306e\u4f5c\u6210\u4ee5\u964d\u306e\u30ea\u30b9\u30c8\u3078\u306e\u8ffd\u52a0\u3001\u524a\u9664\u3001\u307e\u305f\u306f\u5909\u66f4\u3092\u53cd\u6620\u3057\u307e\u305b\u3093\u3002<\/font><\/p>\n
\u30a4\u30c6\u30ec\u30fc\u30bf\u81ea\u4f53\u306b\u5bfe\u3059\u308b\u8981\u7d20\u5909\u66f4\u64cd\u4f5c(remove\u3001set\u304a\u3088\u3073add)\u306f\u30b5\u30dd\u30fc\u30c8\u3055\u308c\u307e\u305b\u3093\u3002\u3053\u308c\u3089\u306e\u30e1\u30bd\u30c3\u30c9\u306f\u3001UnsupportedOperationException\u3092\u30b9\u30ed\u30fc\u3057\u307e\u3059\u3002 <\/font><\/p>\n
null\u3092\u542b\u3080\u3059\u3079\u3066\u306e\u8981\u7d20\u304c\u8a31\u53ef\u3055\u308c\u307e\u3059\u3002 <\/font><\/p>\n
\u30e1\u30e2\u30ea\u30fc\u6574\u5408\u6027\u52b9\u679c: \u307b\u304b\u306e\u4e26\u884c\u51e6\u7406\u30b3\u30ec\u30af\u30b7\u30e7\u30f3\u3068\u540c\u69d8\u3001\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092CopyOnWriteArrayList\u306b\u914d\u7f6e\u3059\u308b\u524d\u306e\u30b9\u30ec\u30c3\u30c9\u5185\u306e\u30a2\u30af\u30b7\u30e7\u30f3\u306f\u3001\u5225\u306e\u30b9\u30ec\u30c3\u30c9\u3067\u306e\u305d\u306e\u8981\u7d20\u3078\u306e\u30a2\u30af\u30bb\u30b9\u307e\u305f\u306fCopyOnWriteArrayList\u304b\u3089\u306e\u524a\u9664\u306b\u7d9a\u304f\u30a2\u30af\u30b7\u30e7\u30f3\u3088\u308a\u3082\u524d\u306b\u767a\u751f\u3057\u307e\u3059\u3002 <\/font><\/p>\n
\u3053\u306e\u30af\u30e9\u30b9\u306f\u3001Java Collections Framework\u306e\u30e1\u30f3\u30d0\u30fc\u3067\u3059\u3002<\/font><\/p>\n
\u3064\u307e\u308a\u3001\u30b9\u30ca\u30c3\u30d7\u30b7\u30e7\u30c3\u30c8\uff08\u30b3\u30d4\u30fc\uff09\u3092\u4f5c\u3063\u3066\u305d\u308c\u3092\u30a4\u30c6\u30ec\u30fc\u30b7\u30e7\u30f3\u3059\u308b\u3053\u3068\u306b\u3088\u3063\u3066\u30b9\u30ec\u30c3\u30c9\u30fb\u30bb\u30fc\u30d5\u3092\u53ef\u80fd\u306b\u3057\u3066\u3044\u308b\u3088\u3046\u3067\u3059\u3002<\/p>\n
private final List<String> friends = new ArrayList<>(16); \u3092<\/p>\n
private final CopyOnWriteArrayList<String> friends = new CopyOnWriteArrayList<>(); \u306b\u5909\u66f4\u3059\u308b\u3060\u3051\u306e\u304a\u624b\u8efd\u4ed5\u69d8\u3067\u3059\u3002<\/p>\n
\u305f\u3060\u3057\u3001CopyOnWriteArrayList<E> \u306f\u521d\u671f\u5bb9\u91cf\u3092\u8a2d\u5b9a\u3067\u304d\u306a\u3044\u306e\u3067\u304a\u9593\u9055\u3044\u306a\u304f\uff01<\/p>\n
\u3044\u304b\u304c\u3067\u3057\u305f\u3067\u3057\u3087\u3046\u304b\uff1f<\/p>\n
\u672c\u5f53\u306b\u53e4\u5178\u7684\u306a\u3042\u308a\u3075\u308c\u305f\u30d1\u30ba\u30eb\u3067\u3059\u304c\u61d0\u304b\u3057\u3055\u3068\u521d\u3081\u3066 java.util.ConcurrentModificationException \u3092\u6295\u3052\u3089\u308c\u305f\u3068\u304d\u306e ??? \u3063\u3066\u306e\u3092\u601d\u3044\u51fa\u3057\u3066\u3044\u305f\u3060\u3051\u308c\u3070\u5e78\u3044\u3067\u3059\u3002<\/p>\n
\u3053\u3053\u3067\u30cd\u30bf\u3070\u3089\u3057\u30fb\u30fb\u30fb\u3000\u3053\u306e\u554f\u984c\u306f \u300cJava \u4e26\u884c\u51e6\u7406\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u300d\u3068\u3044\u3046\u53e4\u3044\u672c\u306b\u3082\u8f09\u3063\u3066\u3044\u308b\u307b\u3069\u8d85\u6709\u540d\u306a\u30cd\u30bf\u3067\u3057\u305f\u3002<\/p>\n
\u3053\u308c\u3060\u3051\u3060\u3068 CoffeeBreak \u30cd\u30bf\u3068\u3057\u3066\u306f\u9762\u767d\u307f\u306b\u6b20\u3051\u3066\u3044\u307e\u3059\u306e\u3067\u30b0\u30ea\u30b3\u306e\u30ad\u30e3\u30e9\u30e1\u30eb\u306e\u304a\u307e\u3051\u306e\u3088\u3046\u306a\u554f\u984c\u3092\u3082\u3046\u4e00\u554f\u3069\u3046\u305e\u3002<\/p>\n
\u3066\u3044\u3046\u304b\u3001\u3053\u308c\u304c\u672c\u984c\u3067\u3059\u3002<\/p>\n
\u30b0\u30ea\u30b3\u306e\u30ad\u30e3\u30e9\u30e1\u30eb\u306e\u304a\u307e\u3051\u306e\u3088\u3046\u306a\u554f\u984c<\/h4>\n
\u6b21\u306e\u30d7\u30ed\u30b0\u30e9\u30e0\u3092\u30b3\u30f3\u30d1\u30a4\u30eb\u3001\u5b9f\u884c\u3059\u308b\u3068\u6a19\u6e96\u51fa\u529b\u306b\u3069\u3093\u306a\u7d50\u679c\u3092\u8868\u793a\u3059\u308b\u3067\u3057\u3087\u3046\u304b\uff1f<\/p>\n
\u305f\u3060\u3057\u3001public static void parkUntil(long deadline) \u30e1\u30bd\u30c3\u30c9\u306e\u7406\u7531\u7121\u304d\u5fa9\u5e30\u306f\u306a\u3044\u3082\u306e\u3068\u3059\u308b\u3002<\/p>\n
package jp.yucchi.coffeebreak;\r\n\r\nimport java.util.concurrent.locks.LockSupport;\r\n\r\npublic class CoffeeBreak {\r\n\r\n    public static void main(String[] args) throws InterruptedException {\r\n\r\n        Thread worker = new Thread(() -> {\r\n            int workCount = -1;\r\n            long start = System.nanoTime();\r\n\r\n            while (true) {\r\n                long stop = System.nanoTime();\r\n                if ((int) ((stop - start) * 1e-9 % 60) > 10) {\r\n                    break;\r\n                } else {\r\n                    int count = (int) ((stop - start) * 1e-9 % 60);\r\n                    if (workCount != count) {\r\n                        workCount = count;\r\n                        if (workCount == 0) {\r\n                            System.out.println(\"\u4eca\u65e5\u3082\u4e00\u65e5\u304c\u3093\u3070\u308b\u305e\u3044!\");\r\n                        } else {\r\n                            System.out.print(workCount + \"\u6642 \");\r\n                        }\r\n                        if (workCount == 3) {\r\n                            final long t = System.currentTimeMillis() + 6_000L;\r\n                            System.out.println(\"\\n\u25a1\uff8co(^-^)\uff7a\uff70\uff8b\uff70\uff8c\uff9e\uff9a\uff72\uff78\");\r\n                            while (true) {\r\n                                LockSupport.parkUntil(t);\r\n                                if (System.currentTimeMillis() >= t) {\r\n                                    System.out.println(\"\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af\u7d42\u4e86\");\r\n                                    break;\r\n                                } else {\r\n                                    System.out.println((int) ((System.nanoTime() - start) * 1e-9 % 60) + \"\u6642\u3084\u3093\u3002 \" + \"\u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~\");\r\n                                }  \r\n                            }\r\n                        }\r\n                    }\r\n                }\r\n            }\r\n        });\r\n\r\n        worker.start();\r\n        LockSupport.unpark(worker);\r\n        Thread.sleep(4_500);\r\n        System.out.println(\"\u305d\u308d\u305d\u308d\u4f11\u61a9\u304a\u308f\u308a\u306b\u3057\u3088\u3046\u304b\uff1f \");\r\n        LockSupport.unpark(worker);\r\n        Thread.sleep(2_000);\r\n        System.out.println(\"(\uff9e \uff40-\u00b4)\/ \uff7a\uff97\uff6f!!  \u4f11\u61a9\u306f3\u6642\u9593\u3060\u305e\u3002\u50cd\u3051\uff01\");\r\n        worker.interrupt();\r\n        while (worker.isAlive());\r\n        System.out.println(\"\\n\u4ed5\u4e8b\u7d42\u308f\u3063\u305f\uff01 \u611b\u3059\u308b\u5bb6\u65cf\u306e\u5143\u3078\u5e30\u308d\u3046\uff01\");\r\n\r\n    }\r\n\r\n}\r\n\r\n<\/pre>\n
(1)<\/strong><\/p>\n
\u4eca\u65e5\u3082\u4e00\u65e5\u304c\u3093\u3070\u308b\u305e\u3044!
1\u6642 2\u6642 3\u6642 
\u25a1\uff8co(^-^)\uff7a\uff70\uff8b\uff70\uff8c\uff9e\uff9a\uff72\uff78
\u305d\u308d\u305d\u308d\u4f11\u61a9\u304a\u308f\u308a\u306b\u3057\u3088\u3046\u304b\uff1f 
4\u6642\u3084\u3093\u3002 \u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~
(\uff9e \uff40-\u00b4)\/ \uff7a\uff97\uff6f!!  \u4f11\u61a9\u306f3\u6642\u9593\u3060\u305e\u3002\u50cd\u3051\uff01
6\u6642\u3084\u3093\u3002 \u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~
6\u6642\u3084\u3093\u3002 \u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~
            .
            .
            .
7\u6642\u3084\u3093\u3002 \u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~
            .
            .
            .
8\u6642\u3084\u3093\u3002 \u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~
8\u6642\u3084\u3093\u3002 \u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~
\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af\u7d42\u4e86
9\u6642 10\u6642 
\u4ed5\u4e8b\u7d42\u308f\u3063\u305f\uff01 \u611b\u3059\u308b\u5bb6\u65cf\u306e\u5143\u3078\u5e30\u308d\u3046\uff01<\/p>\n
(2)<\/strong><\/p>\n
\u4eca\u65e5\u3082\u4e00\u65e5\u304c\u3093\u3070\u308b\u305e\u3044!
1\u6642 2\u6642 3\u6642 
\u25a1\uff8co(^-^)\uff7a\uff70\uff8b\uff70\uff8c\uff9e\uff9a\uff72\uff78
3\u6642\u3084\u3093\u3002 \u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~
\u305d\u308d\u305d\u308d\u4f11\u61a9\u304a\u308f\u308a\u306b\u3057\u3088\u3046\u304b\uff1f 
4\u6642\u3084\u3093\u3002 \u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~
(\uff9e \uff40-\u00b4)\/ \uff7a\uff97\uff6f!!  \u4f11\u61a9\u306f3\u6642\u9593\u3060\u305e\u3002\u50cd\u3051\uff01
6\u6642\u3084\u3093\u3002 \u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~
6\u6642\u3084\u3093\u3002 \u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~
            .
            .
            .
7\u6642\u3084\u3093\u3002 \u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~
            .
            .
            .
8\u6642\u3084\u3093\u3002 \u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~
8\u6642\u3084\u3093\u3002 \u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~
\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af\u7d42\u4e86
9\u6642 10\u6642 
\u4ed5\u4e8b\u7d42\u308f\u3063\u305f\uff01 \u611b\u3059\u308b\u5bb6\u65cf\u306e\u5143\u3078\u5e30\u308d\u3046\uff01<\/p>\n
(3)<\/strong><\/p>\n
\u5b9f\u884c\u6642\u4f8b\u5916<\/p>\n
(4)<\/strong><\/p>\n
\u30b3\u30f3\u30d1\u30a4\u30eb\u30a8\u30e9\u30fc<\/p>\n
 <\/p>\n
\u7b54\u3048<\/h4>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
\u6b63\u89e3\u306f\u2025\u2025<\/p>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
(1)<\/strong> \u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002<\/p>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
(2)<\/strong> \u3067\u3059\u3002<\/p>\n
        worker.start();\r\n        LockSupport.unpark(worker);\r\n        Thread.sleep(4_500);\r\n        System.out.println(\"\u305d\u308d\u305d\u308d\u4f11\u61a9\u304a\u308f\u308a\u306b\u3057\u3088\u3046\u304b\uff1f \");\r\n        LockSupport.unpark(worker);\r\n        Thread.sleep(2_000);\r\n        System.out.println(\"(\uff9e \uff40-\u00b4)\/ \uff7a\uff97\uff6f!!  \u4f11\u61a9\u306f3\u6642\u9593\u3060\u305e\u3002\u50cd\u3051\uff01\");\r\n        worker.interrupt();\r\n        while (worker.isAlive());\r\n        System.out.println(\"\\n\u4ed5\u4e8b\u7d42\u308f\u3063\u305f\uff01 \u611b\u3059\u308b\u5bb6\u65cf\u306e\u5143\u3078\u5e30\u308d\u3046\uff01\");\r\n<\/pre>\n
worker \u30b9\u30ec\u30c3\u30c9\u304c\u958b\u59cb\u3055\u308c\u305f\u76f4\u5f8c\u306b LockSupport.unpark(worker); \u304c\u5b9f\u884c\u3055\u308c\u307e\u3059\u3002(45 \u884c\u76ee)<\/p>\n
\u3053\u308c\u306f\u5f15\u6570\u3067\u6307\u5b9a\u3057\u305f\u30b9\u30ec\u30c3\u30c9\u306b\u30d1\u30fc\u30df\u30c3\u30c8\u3092\u4e0e\u3048\u307e\u3059\u3002<\/p>\n
\u3053\u306e\u30d1\u30fc\u30df\u30c3\u30c8\u306f\u4e00\u3064\u3060\u3051\u84c4\u7a4d\u53ef\u80fd\u3068\u306a\u308a\u307e\u3059\u3002<\/p>\n
\u3088\u3063\u3066\u3001worker \u30b9\u30ec\u30c3\u30c9\u306e LockSupport.parkUntil(t); (30 \u884c\u76ee) \u306f\u30d1\u30fc\u30df\u30c3\u30c8\u3092\u6d88\u8cbb\u3057\u3066\u3059\u3050\u306b\u30ea\u30bf\u30fc\u30f3\u3055\u308c\u307e\u3059\u3002<\/p>\n
\u6545\u306b\u6a19\u6e96\u51fa\u529b\u306b<\/p>\n
\u4eca\u65e5\u3082\u4e00\u65e5\u304c\u3093\u3070\u308b\u305e\u3044!
1\u6642 2\u6642 3\u6642 
\u25a1\uff8co(^-^)\uff7a\uff70\uff8b\uff70\uff8c\uff9e\uff9a\uff72\uff78
3\u6642\u3084\u3093\u3002 \u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~<\/font><\/p>\n
\u3068\u8868\u793a\u3055\u308c\u307e\u3059\u3002<\/p>\n
\u305d\u3057\u3066 48\u884c\u76ee\u306e LockSupport.unpark(worker); \u304c\u5b9f\u884c\u3055\u308c\u3066<\/p>\n
\u305d\u308d\u305d\u308d\u4f11\u61a9\u304a\u308f\u308a\u306b\u3057\u3088\u3046\u304b\uff1f 
4\u6642\u3084\u3093\u3002 \u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~<\/font><\/p>\n
\u3068\u7d9a\u304d\u307e\u3059\u3002<\/p>\n
while \u30eb\u30fc\u30d7\u3067\u518d\u3073 LockSupport.parkUntil(t); \u304c\u5b9f\u884c\u3055\u308c\u307e\u3059\u3002<\/p>\n
\u6307\u5b9a\u3055\u308c\u305f\u5f85\u6a5f\u6642\u9593\u3092\u7d4c\u904e\u3057\u3066\u306a\u3044\u306e\u3067\u30b9\u30ec\u30c3\u30c9\u306f\u518d\u3073\u5f85\u6a5f\u3057\u307e\u3059\u3002<\/p>\n
51 \u884c\u76ee\u3067 worker.interrupt(); \u3068\u5272\u308a\u8fbc\u307f\u3092\u304b\u3051\u307e\u3059\u3002<\/p>\n
\u3068\u3053\u308d\u304c\u3053\u306e\u5272\u308a\u8fbc\u307f\u306b\u5bfe\u3057\u3066 InterruptedException\u304c\u30b9\u30ed\u30fc\u3055\u308c\u307e\u305b\u3093\u3002<\/p>\n
\u5272\u308a\u8fbc\u307f\u306b\u3088\u308b\u51e6\u7406\u3092\u306a\u306b\u3082\u3057\u3066\u3044\u306a\u3044\u306e\u3067 LockSupport.parkUntil(t); \u306b\u3088\u308b\u6307\u5b9a\u3055\u308c\u305f\u5f85\u6a5f\u6642\u9593\u307e\u3067\u306e\u5f85\u6a5f\u306f\u89e3\u9664\u3055\u308c\u3059\u3050\u306b\u30ea\u30bf\u30fc\u30f3\u3055\u308c\u307e\u3059\u3002<\/p>\n
while \u30eb\u30fc\u30d7\u3067\u6307\u5b9a\u3055\u308c\u305f\u5f85\u6a5f\u6642\u9593\u307e\u3067\u5ef6\u3005\u3068\u6a19\u6e96\u51fa\u529b\u306b\u6b21\u306e\u3088\u3046\u306b\u51fa\u529b\u3055\u308c\u307e\u3059\u3002<\/p>\n
(\uff9e \uff40-\u00b4)\/ \uff7a\uff97\uff6f!!  \u4f11\u61a9\u306f3\u6642\u9593\u3060\u305e\u3002\u50cd\u3051\uff01
6\u6642\u3084\u3093\u3002 \u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~
6\u6642\u3084\u3093\u3002 \u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~
            .
            .
            .
7\u6642\u3084\u3093\u3002 \u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~
            .
            .
            .
8\u6642\u3084\u3093\u3002 \u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~
8\u6642\u3084\u3093\u3002 \u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~
\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af\u7d42\u4e86
9\u6642 10\u6642 
\u4ed5\u4e8b\u7d42\u308f\u3063\u305f\uff01 \u611b\u3059\u308b\u5bb6\u65cf\u306e\u5143\u3078\u5e30\u308d\u3046\uff01
<\/font><\/p>\n
\u3053\u308c\u3092\u30b9\u30c3\u30ad\u30ea\u3057\u305f\u51fa\u529b\u306b\u3059\u308b\u305f\u3081\u306b\u306f 45 \u884c\u76ee\u306e LockSupport.unpark(worker); \u3092\u524a\u9664\u3057\u3001<\/p>\n
worker \u30b9\u30ec\u30c3\u30c9\u3078\u306e\u5272\u308a\u8fbc\u307f\u306e\u5bfe\u51e6\u3092\u6b21\u306e\u3088\u3046\u306b\u3059\u308c\u3070\u671f\u5f85\u3059\u308b\u51fa\u529b\u304c\u5f97\u3089\u308c\u307e\u3059\u3002<\/p>\n
                        if (workCount == 3) {\r\n                            final long t = System.currentTimeMillis() + 6_000L;\r\n                            System.out.println(\"\\n\u25a1\uff8co(^-^)\uff7a\uff70\uff8b\uff70\uff8c\uff9e\uff9a\uff72\uff78\");\r\n                            while (true) {\r\n                                LockSupport.parkUntil(t);\r\n                                if (System.currentTimeMillis() >= t) {\r\n                                    System.out.println(\"\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af\u7d42\u4e86\");\r\n                                    break;\r\n                                } else {\r\n                                    if (Thread.currentThread().isInterrupted()) {\r\n                                        System.out.println(\"\u306f\u3044\u3001\u306f\u3044\u3002\");\r\n                                        break;\r\n                                    }\r\n                                    System.out.println((int) ((System.nanoTime() - start) * 1e-9 % 60) + \"\u6642\u3084\u3093\u3002 \" + \"\u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~\");\r\n                                }\r\n                                \r\n                            }\r\n                        }\r\n<\/pre>\n
\u4eca\u65e5\u3082\u4e00\u65e5\u304c\u3093\u3070\u308b\u305e\u3044!
1\u6642 2\u6642 3\u6642 
\u25a1\uff8co(^-^)\uff7a\uff70\uff8b\uff70\uff8c\uff9e\uff9a\uff72\uff78
\u305d\u308d\u305d\u308d\u4f11\u61a9\u304a\u308f\u308a\u306b\u3057\u3088\u3046\u304b\uff1f 
4\u6642\u3084\u3093\u3002 \u307e\u3060\u3001\u30b3\u30fc\u30d2\u30fc\u30d6\u30ec\u30a4\u30af \u30bf\u30a4\u30e0\u3002 \u25a1\uff8co(^O^)\uff8c\uff9f\uff8a\uff67~
(\uff9e \uff40-\u00b4)\/ \uff7a\uff97\uff6f!!  \u4f11\u61a9\u306f3\u6642\u9593\u3060\u305e\u3002\u50cd\u3051\uff01
\u306f\u3044\u3001\u306f\u3044\u3002
6\u6642 7\u6642 8\u6642 9\u6642 10\u6642 \u4ed5\u4e8b\u7d42\u308f\u3063\u305f\uff01 \u611b\u3059\u308b\u5bb6\u65cf\u306e\u5143\u3078\u5e30\u308d\u3046\uff01<\/font><\/p>\n
\u53c2\u8003\u306b\u3053\u306e\u30d7\u30ed\u30b0\u30e9\u30e0\u3067\u4f7f\u3063\u305f java.lang.Object java.util.concurrent.locks.LockSupport \u30af\u30e9\u30b9\u306e\u30e1\u30bd\u30c3\u30c9\u306e Javadoc \u3092\u8f09\u305b\u3066\u304a\u304d\u307e\u3059\u3002<\/p>\n
public static void unpark(Thread thread)<\/strong><\/font><\/p>\n
\u6307\u5b9a\u3055\u308c\u305f\u30b9\u30ec\u30c3\u30c9\u306e\u30d1\u30fc\u30df\u30c3\u30c8\u304c\u4f7f\u7528\u53ef\u80fd\u3067\u306a\u3044\u5834\u5408\u306b\u3001\u4f7f\u7528\u53ef\u80fd\u306b\u3057\u307e\u3059\u3002<\/font><\/p>\n
\u30b9\u30ec\u30c3\u30c9\u304cpark\u3067\u30d6\u30ed\u30c3\u30af\u3055\u308c\u305f\u5834\u5408\u306f\u3001\u30d6\u30ed\u30c3\u30af\u3092\u89e3\u9664\u3057\u307e\u3059\u3002<\/font><\/p>\n
\u305d\u308c\u4ee5\u5916\u306e\u5834\u5408\u306f\u3001\u305d\u306epark\u306e\u6b21\u56de\u306e\u547c\u51fa\u3057\u304c\u30d6\u30ed\u30c3\u30af\u3055\u308c\u306a\u3044\u3088\u3046\u4fdd\u8a3c\u3055\u308c\u307e\u3059\u3002<\/font><\/p>\n
\u6307\u5b9a\u3055\u308c\u305f\u30b9\u30ec\u30c3\u30c9\u304c\u8d77\u52d5\u3057\u3066\u3044\u306a\u3044\u5834\u5408\u3001\u3053\u306e\u64cd\u4f5c\u306e\u52b9\u679c\u306f\u4e00\u5207\u4fdd\u8a3c\u3055\u308c\u307e\u305b\u3093\u3002<\/font><\/p>\n
\u30d1\u30e9\u30e1\u30fc\u30bf:thread – unpark\u3092\u5b9f\u884c\u3059\u308b\u30b9\u30ec\u30c3\u30c9\u307e\u305f\u306fnull\u3002\u305d\u306e\u5834\u5408\u3001\u3053\u306e\u64cd\u4f5c\u306b\u52b9\u679c\u306f\u306a\u3044<\/font><\/p>\n
public static void parkUntil(long deadline)<\/strong><\/font><\/p>\n
\u30d1\u30fc\u30df\u30c3\u30c8\u304c\u5229\u7528\u53ef\u80fd\u3067\u306a\u3044\u5834\u5408\u3001\u6307\u5b9a\u3055\u308c\u305f\u671f\u9650\u307e\u3067\u3001\u30b9\u30ec\u30c3\u30c9\u306e\u30b9\u30b1\u30b8\u30e5\u30fc\u30ea\u30f3\u30b0\u306b\u95a2\u3057\u3066\u73fe\u5728\u306e\u30b9\u30ec\u30c3\u30c9\u3092\u7121\u52b9\u306b\u3057\u307e\u3059\u3002
 
\u30d1\u30fc\u30df\u30c3\u30c8\u304c\u4f7f\u7528\u53ef\u80fd\u306a\u5834\u5408\u3001\u3053\u308c\u306f\u6d88\u8cbb\u3055\u308c\u3001\u547c\u51fa\u3057\u306f\u305f\u3060\u3061\u306b\u5fa9\u5e30\u3057\u307e\u3059\u3002<\/font><\/p>\n
\u305d\u308c\u4ee5\u5916\u306e\u5834\u5408\u3001\u73fe\u5728\u306e\u30b9\u30ec\u30c3\u30c9\u306f\u3001\u30b9\u30ec\u30c3\u30c9\u30fb\u30b9\u30b1\u30b8\u30e5\u30fc\u30ea\u30f3\u30b0\u306b\u95a2\u3057\u3066\u7121\u52b9\u306b\u306a\u308a\u3001\u6b21\u306e4\u3064\u306e\u3044\u305a\u308c\u304b\u304c\u8d77\u304d\u308b\u307e\u3067\u5f85\u6a5f\u3057\u307e\u3059\u3002
 
\u2022\u307b\u304b\u306e\u30b9\u30ec\u30c3\u30c9\u304c\u3001\u73fe\u5728\u306e\u30b9\u30ec\u30c3\u30c9\u3092\u30bf\u30fc\u30b2\u30c3\u30c8\u3068\u3057\u3066unpark\u3092\u547c\u3073\u51fa\u3059\u3002 
\u2022\u307b\u304b\u306e\u30b9\u30ec\u30c3\u30c9\u304c\u73fe\u5728\u306e\u30b9\u30ec\u30c3\u30c9\u306b\u5272\u308a\u8fbc\u307f\u3092\u884c\u3046\u3002\u307e\u305f\u306f 
\u2022\u6307\u5b9a\u3055\u308c\u305f\u671f\u9650\u304c\u7d4c\u904e\u3059\u308b\u3002\u307e\u305f\u306f 
\u2022\u547c\u51fa\u3057\u304c\u3001\u898b\u305b\u304b\u3051\u3067(\u7406\u7531\u3082\u306a\u304f)\u5fa9\u5e30\u3059\u308b\u3002 <\/font><\/p>\n
\u3053\u306e\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u3053\u308c\u3089\u306e\u3069\u308c\u304c\u30e1\u30bd\u30c3\u30c9\u5fa9\u5e30\u306e\u539f\u56e0\u3068\u306a\u3063\u305f\u304b\u306f\u30ec\u30dd\u30fc\u30c8\u3057\u307e\u305b\u3093\u3002<\/font><\/p>\n
\u547c\u51fa\u3057\u5074\u306f\u3001\u30b9\u30ec\u30c3\u30c9\u306e\u521d\u56depark\u306e\u539f\u56e0\u3068\u306a\u3063\u305f\u72b6\u614b\u3092\u518d\u30c1\u30a7\u30c3\u30af\u3059\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002<\/font><\/p>\n
\u547c\u51fa\u3057\u5074\u306f\u3001\u30b9\u30ec\u30c3\u30c9\u306e\u5272\u8fbc\u307f\u72b6\u614b\u3084\u3001\u5fa9\u5e30\u6642\u306e\u73fe\u5728\u6642\u523b\u306a\u3069\u3082\u5224\u5b9a\u3067\u304d\u307e\u3059\u3002<\/font><\/p>\n
\u30d1\u30e9\u30e1\u30fc\u30bf:deadline – \u5f85\u6a5f\u7528\u306e\u3001\u5143\u671f\u304b\u3089\u306e\u30df\u30ea\u79d2\u5358\u4f4d\u306e\u7d76\u5bfe\u6642\u9593<\/font><\/p>\n
\u4ee5\u4e0a\u3001Coffee Break \u30cd\u30bf\u3067\u3057\u305f\u3002(^_^)<\/p>\n
\u3055\u3089\u306b\u3001\u304a\u307e\u3051<\/h4>\n
\u6b21\u306e\u30d7\u30ed\u30b0\u30e9\u30e0\u306e\u51fa\u529b\u7d50\u679c\u3092\u7b54\u3048\u3088\u3002<\/p>\n
package jp.yucchi.wisecalculation;\r\n\r\npublic class WiseCalculation {\r\n\r\n    public static void main(String[] args) {\r\n\r\n        boolean accuracy = false;\r\n        for (double i = 1.0; i < Double.MAX_VALUE; i++) {\r\n            if (Math.log(i) != StrictMath.log(i)) {\r\n                accuracy = true;\r\n                break;\r\n            }\r\n        }\r\n        if (accuracy) {\r\n            System.out.println(\"Results of Math and StrictMath were not the same.\");\r\n        } else {\r\n            System.out.println(\"Results of Math and StrictMath were the same.\");\r\n        }\r\n        \r\n        System.out.println(Math.floorDiv(-4, 3));\r\n        System.out.println(Math.floorDiv(Long.MIN_VALUE, -1) == Long.MIN_VALUE);\r\n        \r\n        System.out.println(Math.floorMod(-4, 3) == Math.floorMod(4, -3));\r\n\r\n    }\r\n\r\n}\r\n<\/pre>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
\u7b54\u3048<\/h4>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
Results of Math and StrictMath were not the same.
-2
true
false<\/p>\n
\u3053\u308c\u306f\u30af\u30a4\u30ba\u8981\u7d20\u3082\u5f15\u3063\u304b\u3051\u8981\u7d20\u3082\u307e\u308b\u3067\u7121\u3044\u3067\u3059\u3002<\/p>\n
\u5f37\u3044\u3066\u3042\u3052\u308c\u3070\uff13\u884c\u76ee\u306e\u51fa\u529b\u7d50\u679c\u304f\u3089\u3044\u3067\u3059\u306d\u3002<\/p>\n
\u3088\u304f\u3042\u308b\u30aa\u30fc\u30d0\u30fc\u30d5\u30ed\u30fc\u306d\u305f\u3067\u3059\u3002(^_^;<\/p>\n
API \u30c9\u30ad\u30e5\u30e1\u30f3\u30c8\u306b\u3059\u3079\u3066\u89e3\u8aac\u3057\u3066\u3042\u308a\u307e\u3059\u306e\u3067\u77e5\u3089\u306a\u304f\u3066\u8208\u5473\u306e\u3042\u308b\u4eba\u306f\u8997\u3044\u3066\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\n
java.lang.Object java.lang.Math public static double log(double a)<\/a><\/p>\n
java.lang.Object java.lang.StrictMath public static double log(double a)<\/a><\/p>\n
public static int floorDiv(int x, int y)<\/a><\/p>\n
public static int floorMod(int x, int y)<\/a><\/p>\n
\u4ee5\u4e0a\u3001\u304a\u7d42\u3044\uff01<\/p>\n
Hatena \u30bf\u30b0: Java<\/a><\/div>\n
\n            
\u3053\u306e\u30a8\u30f3\u30c8\u30ea\u30fc\u3092\u306f\u3066\u306a\u30d6\u30c3\u30af\u30de\u30fc\u30af\u306b\u8ffd\u52a0<\/a><\/div>\n            
Facebook \u306b\u30b7\u30a7\u30a2<\/a><\/div>\n            
<\/g:plusone><\/div>\n            
Tweet<\/a><\/div>\n    <\/div>\n
\n","protected":false},"excerpt":{"rendered":"
\u3053\u306e\u30a8\u30f3\u30c8\u30ea\u30fc\u306f http:\/\/qiita.com\/advent-calendar\/2016\/java_puzzlers \u306e 21 \u65e5\u76ee\u3067\u3059\u3002 \u6628\u65e5\u306f @zr_tex8r \u3055\u3093\u306e\u306e\u300c\u30eb\u30fc\u30d7\u4ee5\u5916\u306e\u6587\u306b\u30e9\u30d9\u30eb\u306f\u4ed8\u3051\u3089\u308c\u308b\u304b\uff1f\u300d\u3067\u3057\u305f\u3002 \u660e\u65e5\u306f @khasunuma \u3055\u3093\u306e\u300c\u8ab0\u3082\u6295\u7a3f\u3057\u305d\u3046\u306b\u306a\u3044\u306e\u3067\u3001\u3082\u3046\u5c11\u3057\u9811\u5f35\u3063\u3066\u307f\u308b\u300d\u3067\u3059\u3002 \u9023\u65e5\u9ad8\u5ea6\u306a Java Puzzle \u304c\u6295\u7a3f\u3055\u308c\u3066\u3044\u3066\u697d\u3057\u307e\u305b\u3066\u3044\u305f\u3060\u3044\u3066\u307e\u3059\u3002 \u300c\u30b8\u30e3\u30d0\u30c1\u30e7\u30c3\u30c8\u30c7\u30ad\u30eb\u300d\u3068\u3044\u3046\u51c4\u3044\u4eba\u305f\u3061\u306e\u6295\u7a3f\u3067\u30af\u30ea\u30c6\u30a3\u30ab\u30eb\u30d2\u30c3\u30c8\u3092\u98df\u3089\u3063\u3066\u30c0\u30a6\u30f3\u3057\u3066\u307e\u3059\u3002(^_^; \u3053\u3053\u3089\u3078\u3093\u3067 CoffeeBreak \u3068\u3044\u3046\u3053\u3068\u3067\u606f\u629c\u304d\u30d1\u30ba\u30eb\u3067\u30a8\u30f3\u30c8\u30ea\u30fc\u3055\u305b\u3066\u3044\u305f\u3060\u304d\u307e\u2026<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[17],"class_list":["post-2285","post","type-post","status-publish","format-standard","hentry","category-java","tag-java"],"_links":{"self":[{"href":"http:\/\/yucchi.jp\/blog\/index.php?rest_route=\/wp\/v2\/posts\/2285","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/yucchi.jp\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/yucchi.jp\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/yucchi.jp\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/yucchi.jp\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2285"}],"version-history":[{"count":2,"href":"http:\/\/yucchi.jp\/blog\/index.php?rest_route=\/wp\/v2\/posts\/2285\/revisions"}],"predecessor-version":[{"id":2288,"href":"http:\/\/yucchi.jp\/blog\/index.php?rest_route=\/wp\/v2\/posts\/2285\/revisions\/2288"}],"wp:attachment":[{"href":"http:\/\/yucchi.jp\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2285"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/yucchi.jp\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2285"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/yucchi.jp\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2285"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}