\u91cd\u6392\u5e8f\u901a\u5e38\u662f\u7f16\u8bd1\u5668\u6216\u8fd0\u884c\u65f6\u73af\u5883\u4e3a\u4e86\u4f18\u5316\u7a0b\u5e8f\u6027\u80fd\u800c\u91c6\u53d6\u7684\u5bf9\u6307\u4ee4\u8fdb\u884c\u91cd\u65b0\u6392\u5e8f\u6267\u884c\u7684\u4e00 \u79cd\u624b\u6bb5\u3002\u91cd\u6392\u5e8f\u5206\u4e3a\u4e24\u7c7b\uff1a\u7f16\u8bd1\u671f\u91cd\u6392\u5e8f\u548c\u8fd0\u884c\u671f\u91cd\u6392\u5e8f\uff0c\u5206\u522b\u5bf9\u5e94\u7f16\u8bd1\u65f6\u548c\u8fd0\u884c\u65f6\u73af\u5883\u3002
\n\u7f16\u8bd1\u671f\u91cd\u6392\u5e8f\u7684\u5178\u578b\u5c31\u662f\u901a\u8fc7\u8c03\u6574\u6307\u4ee4\u987a\u5e8f\uff0c\u5728\u4e0d\u6539\u53d8\u7a0b\u5e8f\u8bed\u4e49\u7684\u524d\u63d0\u4e0b\uff0c\u5c3d\u53ef\u80fd\u51cf\u5c11\u5bc4\u5b58\u5668 \u7684\u8bfb\u53d6\u3001\u5b58\u50a8\u6b21\u6570\uff0c\u5145\u5206\u590d\u7528\u5bc4\u5b58\u5668\u7684\u5b58\u50a8\u503c\u3002
\n\/\/\u4ee5\u4e0b\u64cd\u4f5c\u5728\u540c\u4e00\u4e2a\u7ebf\u7a0b\u4e2d\u6267\u884c
\nint i = 1;
\nint j = 2;
\nint j = 2\u7684\u4ee3\u7801\u5b8c\u5168\u53ef\u80fd\u5148\u88ab\u5904\u7406\u5668\u6267\u884c\uff0c\u8fd9\u5e76\u4e0d\u5f71\u54cd\u5148\u884c\u5148\u53d1\u751f\u539f\u5219\uff0c\u56e0\u4e3a\u6211\u4eec\u5728\u8fd9\u6761\u7ebf \u7a0b\u4e2d\u6ca1\u6709\u529e\u6cd5\u611f\u77e5\u5230\u8fd9\u70b9\u3002\uff08\u90fd\u662f\u8d4b\u503c\u64cd\u4f5c\uff0c\u65e0\u8bba\u5148\u53d1\u751f\u54ea\u4e00\u4e2a\uff0c\u6700\u7ec8\u7ed3\u679c\u90fd\u4e0e\u987a\u5e8f\u6267\u884c\u4e00\u6837\uff09\u3002 \u4f46\u5982\u679c\u6709\u5176\u4ed6\u7ebf\u7a0b\u5728\u8bfb\u53d6\u8fd9\u4e24\u4e2a\u503c\uff0c\u91cd\u6392\u5e8f\u5c31\u4f1a\u9020\u6210\u8bfb\u53d6\u9519\u8bef\uff01
\n\u5bf9\u4e8e\u5355\u4e00\u7ebf\u7a0b\uff0c\u5982\u679c\u6709\u529e\u6cd5\u611f\u77e5\u5230\u8fd9\u70b9\uff0c\u5373int a = 1; int b = a;\u90a3\u4e48\u5c31\u4e0d\u80fd\u91cd\u6392\u5e8f\u3002
\n\u5982\u679c\u4e24\u4e2a\u64cd\u4f5c\u8bbf\u95ee\u540c\u4e00\u4e2a\u53d8\u91cf\uff0c\u4e14\u8fd9\u4e24\u4e2a\u64cd\u4f5c\u4e2d\u6709\u4e00\u4e2a\u4e3a\u5199\u64cd\u4f5c\uff0c\u6b64\u65f6\u8fd9\u4e24\u4e2a\u64cd\u4f5c\u4e4b\u95f4\u5c31\u5b58\u5728 \u6570\u636e\u4f9d\u8d56\u3002\u6570\u636e\u4f9d\u8d56\u5206\u4e0b\u5217\u4e09\u79cd\u7c7b\u578b\uff1a
\n\u540d\u79f0\t\u4ee3\u7801\u793a\u4f8b\t\u8bf4\u660e<\/p>\n
\u5199\u540e\u8bfb\ta = l;b = a;\t\u5199\u4e00\u4e2a\u53d8\u91cf\u4e4b\u540e\uff0c\u518d\u8bfb\u8fd9\u4e2a\t\u4f4d\u7f6e<\/p>\n
\u5199\u540e\u5199\ta = l;a = 2;\t\u5199\u4e00\u4e2a\u53d8\u91cf\u4e4b\u540e\uff0c\u518d\u5199\u8fd9\u4e2a\t\u53d8\u91cf
\n\u8bfb\u540e\u5199
\na = b;b = 1;\t\u8bfb\u4e00\u4e2a\u53d8\u91cf\u4e4b\u540e\u518d\u5199\u8fd9\u4e2a\t\u53d8\u91cf<\/p>\n
\u4e0a\u9762\u4e09\u79cd\u60c5\u51b5\uff0c\u53ea\u8981\u91cd\u6392\u5e8f\u4e24\u4e2a\u64cd\u4f5c\u7684\u6267\u884c\u987a\u5e8f\uff0c\u7a0b\u5e8f\u7684\u6267\u884c\u7ed3\u679c\u5c06\u4f1a\u88ab\u6539\u53d8\u3002\u6240\u4ee5\uff0c\u7f16\u8bd1\u5668 \u548c\u5904\u7406\u5668\u5728\u91cd\u6392\u5e8f\u65f6\uff0c\u4f1a\u9075\u5b88\u6570\u636e\u4f9d\u8d56\u6027\uff0c\u7f16\u8bd1\u5668\u548c\u5904\u7406\u5668\u4e0d\u4f1a\u6539\u53d8\u5b58\u5728\u6570\u636e\u4f9d\u8d56\u5173\u7cfb\u7684\u4e24\u4e2a \u64cd\u4f5c\u7684\u6267\u884c\u987a\u5e8f\u3002\u4e5f\u5c31\u662f\u8bf4\uff1a\u5728\u5355\u7ebf\u7a0b\u73af\u5883\u4e0b\uff0c\u6307\u4ee4\u6267\u884c\u7684\u6700\u7ec8\u6548\u679c\u5e94\u5f53\u4e0e\u5176\u5728\u987a\u5e8f\u6267\u884c\u4e0b\u7684 \u6548\u679c\u4e00\u81f4\uff0c\u5426\u5219\u8fd9\u79cd\u4f18\u5316\u4fbf\u4f1a\u5931\u53bb\u610f\u4e49\u3002\u8fd9\u53e5\u8bdd\u6709\u4e2a\u4e13\u4e1a\u672f\u8bed\u53eb\u505aas-if-serial semantics \uff08as-if-serial \u8bed\u4e49\uff09\u3002
\nclass ReorderExamp1e {
\nint a = 0;
\nboolean flag = false;
\npublic void writer() {
\na = 1;\t\/\/\t1
\nflag = true; \/\/ 2
\n}
\npublic void reader() {
\nif (flag) {\t\/\/ 3
\nint i = a * a; \/\/ 4
\n}
\n}
\n}
\nflag\u53d8\u91cf\u662f\u4e2a\u6807\u8bb0\uff0c\u7528\u6765\u6807\u8bc6\u53d8\u91cfa\u662f\u5426\u5df2\u88ab\u5199\u5165\u3002\u8fd9\u91cc\u5047\u8bbe\u6709\u4e24\u4e2a\u7ebf\u7a0bA\u548cB, A\u9996\u5148\u6267\u884c writer()\u65b9\u6cd5\uff0c\u968f\u540eB\u7ebf\u7a0b\u63a5\u7740\u6267\u884creader()\u65b9\u6cd5\u3002\u7ebf\u7a0bB\u5728\u6267\u884c\u64cd\u4f5c4\u65f6\uff0c\u80fd\u5426\u770b\u5230\u7ebf\u7a0bA \u5728\u64cd\u4f5c1\u5bf9\u5171\u4eab\u53d8\u91cfa\u7684\u5199\u5165\uff1f
\n\u7b54\u6848\u662f\uff1a\u4e0d\u4e00\u5b9a\u80fd\u770b\u5230\u3002
\n\u7531\u4e8e\u64cd\u4f5c1\u548c\u64cd\u4f5c2\u6ca1\u6709\u6570\u636e\u4f9d\u8d56\u5173\u7cfb\uff0c\u7f16\u8bd1\u5668\u548c\u5904\u7406\u5668\u53ef\u4ee5\u5bf9\u8fd9\u4e24\u4e2a\u64cd\u4f5c\u91cd\u6392\u5e8f;\u540c\u6837\uff0c\u64cd \u4f5c3\u548c\u64cd\u4f5c4\u6ca1\u6709\u6570\u636e\u4f9d\u8d56\u5173\u7cfb\uff0c\u7f16\u8bd1\u5668\u548c\u5904\u7406\u5668\u4e5f\u53ef\u4ee5\u5bf9\u8fd9\u4e24\u4e2a\u64cd\u4f5c\u91cd\u6392\u5e8f\u3002\u53ef\u4ee5\u4f7f\u7528 synchronized\u4fee\u9970\u8fd9\u4e24\u4e2a\u65b9\u6cd5\uff0c\u6216\u8005\u5c06flag\u8bbe\u4e3avolatile\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898(\u7531\u5148\u884c\u5148\u53d1\u751f\u539f\u5219\u53ef\u77e5)\u3002
\n\u5982\u679cA happens- before B, JMM\u5e76\u4e0d\u8981\u6c42A \u2014\u5b9a\u8981\u5728B\u4e4b\u524d\u6267\u884c\u3002JMM\u4ec5\u4ec5\u8981\u6c42\u524d\u4e00\u4e2a\u64cd\u4f5c (\u6267\u884c\u7684\u7ed3\u679c)\u5bf9\u540e\u4e00\u4e2a\u64cd\u4f5c\u53ef\u89c1\uff0c\u4e14\u524d\u4e00\u4e2a\u64cd\u4f5c\u6309\u987a\u5e8f\u6392\u5728\u7b2c\u4e8c\u4e2a\u64cd\u4f5c\u4e4b\u524d\u3002
\n\u5982\u679c\u64cd\u4f5cA\u7684\u6267\u884c\u7ed3\u679c\u4e0d\u9700\u8981\u5bf9\u64cd\u4f5cB\u53ef\u89c1;\u800c\u4e14\u91cd\u6392\u5e8f\u64cd\u4f5cA\u548c\u64cd\u4f5cB\u540e\u7684\u6267\u884c\u7ed3\u679c\uff0c\u4e0e\u64cd \u4f5cA\u548c\u64cd\u4f5cB\u6309happens- before\u987a\u5e8f\u6267\u884c\u7684\u7ed3\u679c\u4e00\u81f4\u3002\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0cJMM\u4f1a\u8ba4\u4e3a\u8fd9\u79cd\u91cd\u6392 \u5e8f\u5e76\u4e0d\u975e\u6cd5(not illegal) , JMM\u5141\u8bb8\u8fd9\u79cd\u91cd\u6392\u5e8f\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u91cd\u6392\u5e8f\u901a\u5e38\u662f\u7f16\u8bd1\u5668\u6216\u8fd0\u884c\u65f6\u73af\u5883\u4e3a\u4e86\u4f18\u5316\u7a0b\u5e8f\u6027\u80fd\u800c\u91c6\u53d6\u7684\u5bf9\u6307\u4ee4\u8fdb\u884c\u91cd\u65b0\u6392\u5e8f\u6267\u884c\u7684\u4e00 \u79cd\u624b\u6bb5\u3002\u91cd\u6392\u5e8f\u5206\u4e3a\u4e24\u7c7b\uff1a\u7f16\u8bd1 […]<\/p>\n","protected":false},"author":7,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[118],"tags":[],"class_list":["post-10322","post","type-post","status-publish","format-standard","hentry","category-java"],"_links":{"self":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/10322","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/comments?post=10322"}],"version-history":[{"count":1,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/10322\/revisions"}],"predecessor-version":[{"id":10323,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/10322\/revisions\/10323"}],"wp:attachment":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/media?parent=10322"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/categories?post=10322"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/tags?post=10322"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}