{"id":67756,"date":"2026-01-29T05:33:23","date_gmt":"2026-01-28T21:33:23","guid":{"rendered":"https:\/\/www.wsisp.com\/helps\/67756.html"},"modified":"2026-01-29T05:33:23","modified_gmt":"2026-01-28T21:33:23","slug":"%e6%b7%b1%e5%85%a5%e7%90%86%e8%a7%a3-jvm%ef%bc%9ajava-%e8%99%9a%e6%8b%9f%e6%9c%ba%e7%9a%84%e6%a0%b8%e5%bf%83%e5%8e%9f%e7%90%86%e4%b8%8e%e8%b0%83%e4%bc%98%e6%8c%87%e5%8d%97","status":"publish","type":"post","link":"https:\/\/www.wsisp.com\/helps\/67756.html","title":{"rendered":"\u6df1\u5165\u7406\u89e3 JVM\uff1aJava \u865a\u62df\u673a\u7684\u6838\u5fc3\u539f\u7406\u4e0e\u8c03\u4f18\u6307\u5357"},"content":{"rendered":"<h2 id=\"\"><\/h2>\n<p id=\"main-toc\">\u76ee\u5f55<\/p>\n<p id=\"%E5%89%8D%E8%A8%80-toc\" style=\"margin-left:0px\">\u524d\u8a00<\/p>\n<p id=\"%E4%B8%80%E3%80%81JVM%20%E7%AE%80%E4%BB%8B-toc\" style=\"margin-left:40px\">\u4e00\u3001JVM \u7b80\u4ecb<\/p>\n<p id=\"%E4%BA%8C%E3%80%81JVM%20%E5%8F%91%E5%B1%95%E5%8F%B2-toc\" style=\"margin-left:40px\">\u4e8c\u3001JVM \u53d1\u5c55\u53f2<\/p>\n<p id=\"1.%20Sun%20Classic%20VM%EF%BC%881996%20%E5%B9%B4%EF%BC%8CJDK1.0%EF%BC%89-toc\" style=\"margin-left:80px\">1. 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id=\"%EF%BC%881%EF%BC%89%E5%BC%95%E7%94%A8%E8%AE%A1%E6%95%B0%E6%B3%95%EF%BC%88%E6%B7%98%E6%B1%B0%EF%BC%89-toc\" style=\"margin-left:120px\">&#xff08;1&#xff09;\u5f15\u7528\u8ba1\u6570\u6cd5&#xff08;\u6dd8\u6c70&#xff09;<\/p>\n<p id=\"%EF%BC%882%EF%BC%89%E5%8F%AF%E8%BE%BE%E6%80%A7%E5%88%86%E6%9E%90%E7%AE%97%E6%B3%95%EF%BC%88%E4%B8%BB%E6%B5%81%EF%BC%89-toc\" style=\"margin-left:120px\">&#xff08;2&#xff09;\u53ef\u8fbe\u6027\u5206\u6790\u7b97\u6cd5&#xff08;\u4e3b\u6d41&#xff09;<\/p>\n<p id=\"%EF%BC%883%EF%BC%89%E5%BC%95%E7%94%A8%E7%9A%84%E6%89%A9%E5%B1%95%E5%88%86%E7%B1%BB%EF%BC%88JDK1.2%EF%BC%89-toc\" style=\"margin-left:120px\">&#xff08;3&#xff09;\u5f15\u7528\u7684\u6269\u5c55\u5206\u7c7b&#xff08;JDK1.2&#xff09;<\/p>\n<p id=\"2.%20%E5%9E%83%E5%9C%BE%E5%9B%9E%E6%94%B6%E7%AE%97%E6%B3%95-toc\" style=\"margin-left:80px\">2. \u5783\u573e\u56de\u6536\u7b97\u6cd5<\/p>\n<p id=\"%EF%BC%881%EF%BC%89%E6%A0%87%E8%AE%B0%20-%20%E6%B8%85%E9%99%A4%E7%AE%97%E6%B3%95%EF%BC%88%E5%9F%BA%E7%A1%80%EF%BC%89-toc\" 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id=\"%E9%9D%A2%E8%AF%95%E9%A2%98%EF%BC%9AMinor%20GC%20%E4%B8%8E%20Full%20GC%20%E7%9A%84%E5%8C%BA%E5%88%AB-toc\" style=\"margin-left:120px\">\u9762\u8bd5\u9898&#xff1a;Minor GC \u4e0e Full GC \u7684\u533a\u522b<\/p>\n<p id=\"3.%20%E5%9E%83%E5%9C%BE%E6%94%B6%E9%9B%86%E5%99%A8%EF%BC%88HotSpot%EF%BC%89-toc\" style=\"margin-left:80px\">3. \u5783\u573e\u6536\u96c6\u5668&#xff08;HotSpot&#xff09;<\/p>\n<p id=\"%EF%BC%881%EF%BC%89%E6%A0%B8%E5%BF%83%E6%A6%82%E5%BF%B5-toc\" style=\"margin-left:120px\">&#xff08;1&#xff09;\u6838\u5fc3\u6982\u5ff5<\/p>\n<p id=\"%EF%BC%882%EF%BC%89%E6%94%B6%E9%9B%86%E5%99%A8%E5%88%86%E7%B1%BB%E4%B8%8E%E7%89%B9%E6%80%A7-toc\" style=\"margin-left:120px\">&#xff08;2&#xff09;\u6536\u96c6\u5668\u5206\u7c7b\u4e0e\u7279\u6027<\/p>\n<p id=\"%EF%BC%883%EF%BC%89%E9%87%8D%E7%82%B9%E6%94%B6%E9%9B%86%E5%99%A8%E8%AF%A6%E8%A7%A3-toc\" style=\"margin-left:120px\">&#xff08;3&#xff09;\u91cd\u70b9\u6536\u96c6\u5668\u8be6\u89e3<\/p>\n<p id=\"%E2%91%A0%20CMS%20%E6%94%B6%E9%9B%86%E5%99%A8%EF%BC%88%E4%BD%8E%E5%81%9C%E9%A1%BF%E9%A6%96%E9%80%89%EF%BC%89-toc\" style=\"margin-left:160px\">\u2460 CMS \u6536\u96c6\u5668&#xff08;\u4f4e\u505c\u987f\u9996\u9009&#xff09;<\/p>\n<p id=\"%E2%91%A1%20G1%20%E6%94%B6%E9%9B%86%E5%99%A8%EF%BC%88%E5%85%A8%E5%8C%BA%E5%9F%9F%E9%A6%96%E9%80%89%EF%BC%89-toc\" style=\"margin-left:160px\">\u2461 G1 \u6536\u96c6\u5668&#xff08;\u5168\u533a\u57df\u9996\u9009&#xff09;<\/p>\n<p id=\"4.%20%E4%B8%80%E4%B8%AA%E5%AF%B9%E8%B1%A1%E7%9A%84%E4%B8%80%E7%94%9F%EF%BC%88%E6%80%BB%E7%BB%93%EF%BC%89-toc\" style=\"margin-left:80px\">4. \u4e00\u4e2a\u5bf9\u8c61\u7684\u4e00\u751f&#xff08;\u603b\u7ed3&#xff09;<\/p>\n<p id=\"%E4%B8%83%E3%80%81Java%20%E5%86%85%E5%AD%98%E6%A8%A1%E5%9E%8B%EF%BC%88JMM%EF%BC%89-toc\" style=\"margin-left:40px\">\u4e03\u3001Java \u5185\u5b58\u6a21\u578b&#xff08;JMM&#xff09;<\/p>\n<p id=\"1.%20%E6%A0%B8%E5%BF%83%E6%A6%82%E5%BF%B5%EF%BC%9A%E4%B8%BB%E5%86%85%E5%AD%98%E4%B8%8E%E5%B7%A5%E4%BD%9C%E5%86%85%E5%AD%98-toc\" style=\"margin-left:80px\">1. \u6838\u5fc3\u6982\u5ff5&#xff1a;\u4e3b\u5185\u5b58\u4e0e\u5de5\u4f5c\u5185\u5b58<\/p>\n<p id=\"2.%20%E5%86%85%E5%AD%98%E9%97%B4%E4%BA%A4%E4%BA%92%E6%93%8D%E4%BD%9C%EF%BC%888%20%E7%A7%8D%E5%8E%9F%E5%AD%90%E6%93%8D%E4%BD%9C%EF%BC%89-toc\" style=\"margin-left:80px\">2. \u5185\u5b58\u95f4\u4ea4\u4e92\u64cd\u4f5c&#xff08;8 \u79cd\u539f\u5b50\u64cd\u4f5c&#xff09;<\/p>\n<p id=\"3.%20JMM%20%E7%9A%84%E4%B8%89%E5%A4%A7%E6%A0%B8%E5%BF%83%E7%89%B9%E6%80%A7-toc\" style=\"margin-left:80px\">3. JMM \u7684\u4e09\u5927\u6838\u5fc3\u7279\u6027<\/p>\n<p id=\"%EF%BC%881%EF%BC%89%E5%8E%9F%E5%AD%90%E6%80%A7-toc\" style=\"margin-left:120px\">&#xff08;1&#xff09;\u539f\u5b50\u6027<\/p>\n<p id=\"%EF%BC%882%EF%BC%89%E5%8F%AF%E8%A7%81%E6%80%A7-toc\" style=\"margin-left:120px\">&#xff08;2&#xff09;\u53ef\u89c1\u6027<\/p>\n<p id=\"%EF%BC%883%EF%BC%89%E6%9C%89%E5%BA%8F%E6%80%A7-toc\" style=\"margin-left:120px\">&#xff08;3&#xff09;\u6709\u5e8f\u6027<\/p>\n<p id=\"4.%20volatile%20%E5%85%B3%E9%94%AE%E5%AD%97%E8%AF%A6%E8%A7%A3-toc\" style=\"margin-left:80px\">4. volatile \u5173\u952e\u5b57\u8be6\u89e3<\/p>\n<p id=\"%EF%BC%881%EF%BC%89%E6%A0%B8%E5%BF%83%E7%89%B9%E6%80%A7-toc\" style=\"margin-left:120px\">&#xff08;1&#xff09;\u6838\u5fc3\u7279\u6027<\/p>\n<p id=\"%EF%BC%882%EF%BC%89%E4%B8%8D%E4%BF%9D%E8%AF%81%E5%8E%9F%E5%AD%90%E6%80%A7%E7%9A%84%E7%A4%BA%E4%BE%8B-toc\" style=\"margin-left:120px\">&#xff08;2&#xff09;\u4e0d\u4fdd\u8bc1\u539f\u5b50\u6027\u7684\u793a\u4f8b<\/p>\n<p id=\"%EF%BC%883%EF%BC%89volatile%20%E7%9A%84%E9%80%82%E7%94%A8%E5%9C%BA%E6%99%AF-toc\" style=\"margin-left:120px\">&#xff08;3&#xff09;volatile \u7684\u9002\u7528\u573a\u666f<\/p>\n<p id=\"%EF%BC%884%EF%BC%89%E7%A6%81%E6%AD%A2%E6%8C%87%E4%BB%A4%E9%87%8D%E6%8E%92%E5%BA%8F%E7%9A%84%E4%BD%9C%E7%94%A8-toc\" style=\"margin-left:120px\">&#xff08;4&#xff09;\u7981\u6b62\u6307\u4ee4\u91cd\u6392\u5e8f\u7684\u4f5c\u7528<\/p>\n<p id=\"5.%20%E5%8F%8C%E9%87%8D%E6%A3%80%E6%9F%A5%E9%94%81%E5%AE%9A%E5%8D%95%E4%BE%8B%E6%A8%A1%E5%BC%8F%EF%BC%88volatile%20%E5%BA%94%E7%94%A8%EF%BC%89-toc\" style=\"margin-left:80px\">5. \u53cc\u91cd\u68c0\u67e5\u9501\u5b9a\u5355\u4f8b\u6a21\u5f0f&#xff08;volatile \u5e94\u7528&#xff09;<\/p>\n<p id=\"%EF%BC%881%EF%BC%89%E9%97%AE%E9%A2%98%E4%BB%A3%E7%A0%81%EF%BC%88%E6%9C%AA%E7%94%A8%20volatile%EF%BC%89-toc\" style=\"margin-left:120px\">&#xff08;1&#xff09;\u95ee\u9898\u4ee3\u7801&#xff08;\u672a\u7528 volatile&#xff09;<\/p>\n<p id=\"%EF%BC%882%EF%BC%89%E4%BF%AE%E5%A4%8D%E6%96%B9%E6%A1%88%EF%BC%88volatile%20%E4%BF%AE%E9%A5%B0%20instance%EF%BC%89-toc\" style=\"margin-left:120px\">&#xff08;2&#xff09;\u4fee\u590d\u65b9\u6848&#xff08;volatile \u4fee\u9970 instance&#xff09;<\/p>\n<p id=\"%E6%80%BB%E7%BB%93-toc\" style=\"margin-left:0px\">\u603b\u7ed3<\/p>\n<hr \/>\n<h2 id=\"%E5%89%8D%E8%A8%80\">\u524d\u8a00<\/h2>\n<p>\u4f5c\u4e3a Java \u5f00\u53d1\u8005&#xff0c;\u6211\u4eec\u6bcf\u5929\u90fd\u5728\u7f16\u5199\u4ee3\u7801\u3001\u8fd0\u884c\u7a0b\u5e8f\u3002\u4f46\u4f60\u662f\u5426\u66fe\u60f3\u8fc7&#xff0c;\u4f60\u7684\u4ee3\u7801\u662f\u5982\u4f55\u4ece.java\u6587\u4ef6\u53d8\u6210\u53ef\u6267\u884c\u7a0b\u5e8f\u7684&#xff1f;\u4e3a\u4ec0\u4e48\u6709\u65f6\u7a0b\u5e8f\u4f1a\u7a81\u7136\u53d8\u6162\u751a\u81f3\u5d29\u6e83&#xff1f;\u8fd9\u4e9b\u95ee\u9898\u80cc\u540e&#xff0c;\u90fd\u79bb\u4e0d\u5f00 Java \u865a\u62df\u673a\u7684\u652f\u6301\u3002<\/p>\n<p>JVM\u00a0\u5c31\u50cf\u4e00\u4f4d\u5e55\u540e\u5bfc\u6f14&#xff0c;\u5b83\u4e0d\u76f4\u63a5\u53c2\u4e0e\u8868\u6f14&#xff08;\u4e0d\u6267\u884c\u4f60\u7684\u4ee3\u7801&#xff09;&#xff0c;\u4f46\u51b3\u5b9a\u4e86\u8868\u6f14\u7684\u89c4\u5219\u3001\u821e\u53f0\u7684\u5e03\u7f6e\u3001\u6f14\u5458\u7684\u8c03\u5ea6\u3002\u638c\u63e1 JVM \u7684\u5de5\u4f5c\u539f\u7406&#xff0c;\u4e0d\u4ec5\u80fd\u8ba9\u4f60\u5199\u51fa\u66f4\u9ad8\u6548\u7684\u4ee3\u7801&#xff0c;\u8fd8\u80fd\u5728\u9047\u5230\u6027\u80fd\u95ee\u9898\u65f6\u5feb\u901f\u5b9a\u4f4d\u5e76\u89e3\u51b3\u3002<\/p>\n<hr \/>\n<h3 id=\"%E4%B8%80%E3%80%81JVM%20%E7%AE%80%E4%BB%8B\" style=\"background-color:transparent\">\u4e00\u3001JVM \u7b80\u4ecb<\/h3>\n<p>JVM&#xff08;Java Virtual Machine&#xff0c;Java \u865a\u62df\u673a&#xff09;\u662f\u901a\u8fc7\u8f6f\u4ef6\u6a21\u62df\u7684\u3001\u5177\u5907\u5b8c\u6574\u786c\u4ef6\u529f\u80fd\u7684\u8ba1\u7b97\u673a\u7cfb\u7edf&#xff0c;\u8fd0\u884c\u5728\u5b8c\u5168\u9694\u79bb\u7684\u73af\u5883\u4e2d&#xff0c;\u662f Java \u7a0b\u5e8f\u8de8\u5e73\u53f0\u8fd0\u884c\u7684\u6838\u5fc3\u57fa\u7840\u3002<\/p>\n<p>\u4e0e VMware\u3001VirtualBox \u7b49\u901a\u7528\u865a\u62df\u673a\u4e0d\u540c&#xff0c;JVM \u662f\u4e00\u6b3e \u201c\u5b9a\u5236\u5316\u7684\u865a\u62df\u8ba1\u7b97\u673a\u201d&#xff0c;\u6838\u5fc3\u5dee\u5f02\u4f53\u73b0\u5728\u6307\u4ee4\u96c6\u6a21\u62df\u4e0a&#xff1a;<\/p>\n<ul>\n<li>VMware\/VirtualBox&#xff1a;\u6a21\u62df\u7269\u7406 CPU \u7684\u5b8c\u6574\u6307\u4ee4\u96c6&#xff0c;\u5305\u542b\u5927\u91cf\u5bc4\u5b58\u5668&#xff0c;\u53ef\u8fd0\u884c\u4efb\u610f\u64cd\u4f5c\u7cfb\u7edf\u3002<\/li>\n<li>JVM&#xff1a;\u4ec5\u6a21\u62df Java \u5b57\u8282\u7801\u7684\u6307\u4ee4\u96c6&#xff0c;\u4ec5\u4fdd\u7559 PC \u5bc4\u5b58\u5668&#xff08;\u7a0b\u5e8f\u8ba1\u6570\u5668&#xff09;&#xff0c;\u5176\u4ed6\u5bc4\u5b58\u5668\u5747\u88ab\u88c1\u526a&#xff0c;\u4e13\u95e8\u4e3a\u6267\u884c Java \u7a0b\u5e8f\u8bbe\u8ba1\u3002<\/li>\n<\/ul>\n<p>JVM \u7684\u6838\u5fc3\u4ef7\u503c\u662f \u201c\u4e00\u6b21\u7f16\u8bd1&#xff0c;\u5230\u5904\u6267\u884c\u201d\u2014\u2014Java \u6e90\u4ee3\u7801\u7f16\u8bd1\u4e3a\u5b57\u8282\u7801&#xff08;.class \u6587\u4ef6&#xff09;\u540e&#xff0c;\u65e0\u9700\u9488\u5bf9\u4e0d\u540c\u64cd\u4f5c\u7cfb\u7edf\u91cd\u65b0\u7f16\u8bd1&#xff0c;\u53ef\u5728\u4efb\u4f55\u5b89\u88c5\u4e86\u5bf9\u5e94 JVM \u7684\u5e73\u53f0\u4e0a\u8fd0\u884c&#xff0c;\u5c4f\u853d\u4e86\u5e95\u5c42\u786c\u4ef6\u548c\u64cd\u4f5c\u7cfb\u7edf\u7684\u5dee\u5f02\u3002<\/p>\n<h3 id=\"%E4%BA%8C%E3%80%81JVM%20%E5%8F%91%E5%B1%95%E5%8F%B2\">\u4e8c\u3001JVM \u53d1\u5c55\u53f2<\/h3>\n<p>\u81ea 1996 \u5e74 Java 1.0 \u53d1\u5e03\u4ee5\u6765&#xff0c;JVM \u7ecf\u5386\u4e86\u591a\u4ee3\u6f14\u8fdb&#xff0c;\u4e0d\u540c\u5382\u5546\u63a8\u51fa\u4e86\u5404\u5177\u7279\u8272\u7684\u5b9e\u73b0&#xff0c;\u4e3b\u6d41\u7248\u672c\u5982\u4e0b&#xff1a;<\/p>\n<h4 id=\"1.%20Sun%20Classic%20VM%EF%BC%881996%20%E5%B9%B4%EF%BC%8CJDK1.0%EF%BC%89\">1. Sun Classic VM&#xff08;1996 \u5e74&#xff0c;JDK1.0&#xff09;<\/h4>\n<ul>\n<li>\u4e16\u754c\u4e0a\u7b2c\u4e00\u6b3e\u5546\u4e1a JVM&#xff0c;\u4f34\u968f Java 1.0 \u8bde\u751f&#xff0c;\u662f Java \u65e9\u671f\u751f\u6001\u7684\u6838\u5fc3\u652f\u6491\u3002<\/li>\n<li>\u6838\u5fc3\u7279\u6027&#xff1a;\u5185\u90e8\u4ec5\u63d0\u4f9b\u89e3\u91ca\u5668&#xff0c;\u65e0\u5185\u7f6e\u7f16\u8bd1\u5668&#xff08;JIT&#xff09;&#xff1b;\u82e5\u9700\u4f7f\u7528 JIT \u7f16\u8bd1\u5668&#xff0c;\u9700\u989d\u5916\u5916\u6302&#xff0c;\u4e14\u4e00\u65e6\u542f\u7528 JIT&#xff0c;\u5c06\u5b8c\u5168\u63a5\u7ba1\u6267\u884c\u7cfb\u7edf&#xff0c;\u89e3\u91ca\u5668\u4e0d\u518d\u5de5\u4f5c&#xff08;\u4e8c\u8005\u65e0\u6cd5\u534f\u540c&#xff09;\u3002<\/li>\n<li>\u547d\u8fd0&#xff1a;JDK1.4 \u65f6\u88ab\u5b8c\u5168\u6dd8\u6c70&#xff0c;\u76ee\u524d HotSpot \u865a\u62df\u673a\u4e2d\u4ecd\u5185\u7f6e\u4e86\u8be5\u7248\u672c\u7684\u517c\u5bb9\u5b9e\u73b0\u3002<\/li>\n<\/ul>\n<h4 id=\"2.%20Exact%20VM%EF%BC%88JDK1.2%EF%BC%89\">2. Exact VM&#xff08;JDK1.2&#xff09;<\/h4>\n<ul>\n<li>\u4e3a\u89e3\u51b3 Classic VM \u7684\u6027\u80fd\u95ee\u9898\u800c\u751f&#xff0c;\u662f\u73b0\u4ee3\u9ad8\u6027\u80fd JVM \u7684\u96cf\u5f62\u3002<\/li>\n<li>\u6838\u5fc3\u7279\u6027&#xff1a;\u652f\u6301\u70ed\u70b9\u63a2\u6d4b&#xff08;\u8bc6\u522b\u9ad8\u9891\u6267\u884c\u7684 \u201c\u70ed\u70b9\u4ee3\u7801\u201d&#xff0c;\u7f16\u8bd1\u4e3a\u5b57\u8282\u7801\u52a0\u901f\u6267\u884c&#xff09;&#xff1b;\u5b9e\u73b0\u4e86\u89e3\u91ca\u5668\u4e0e\u7f16\u8bd1\u5668\u7684\u6df7\u5408\u5de5\u4f5c\u6a21\u5f0f&#xff0c;\u517c\u987e\u542f\u52a8\u901f\u5ea6\u548c\u8fd0\u884c\u6548\u7387\u3002<\/li>\n<li>\u547d\u8fd0&#xff1a;\u4ec5\u5728 Solaris \u5e73\u53f0\u77ed\u6682\u4f7f\u7528&#xff0c;\u5176\u4ed6\u5e73\u53f0\u4ecd\u6cbf\u7528 Classic VM&#xff0c;\u6700\u7ec8\u56e0\u517c\u5bb9\u6027\u548c\u751f\u6001\u95ee\u9898\u88ab HotSpot \u66ff\u4ee3\u3002<\/li>\n<\/ul>\n<h4 id=\"3.%20HotSpot%20VM%EF%BC%88%E5%BD%93%E5%89%8D%E4%B8%BB%E6%B5%81%EF%BC%89\">3. HotSpot VM&#xff08;\u5f53\u524d\u4e3b\u6d41&#xff09;<\/h4>\n<ul>\n<li>\u5386\u53f2\u6e0a\u6e90&#xff1a;\u6700\u521d\u7531 Longview Technologies \u516c\u53f8\u8bbe\u8ba1&#xff0c;1997 \u5e74\u88ab Sun \u6536\u8d2d&#xff0c;2009 \u5e74\u968f Sun \u88ab Oracle \u6536\u8d2d&#xff1b;JDK1.3 \u65f6\u6210\u4e3a\u9ed8\u8ba4\u865a\u62df\u673a&#xff0c;\u81f3\u4eca\u5360\u636e\u7edd\u5bf9\u5e02\u573a\u5730\u4f4d\u3002<\/li>\n<li>\u6838\u5fc3\u7279\u6027&#xff1a;\u540d\u79f0\u6e90\u4e8e \u201c\u70ed\u70b9\u4ee3\u7801\u63a2\u6d4b\u6280\u672f\u201d\u2014\u2014 \u901a\u8fc7\u8ba1\u6570\u5668\u8bc6\u522b\u6700\u5177\u7f16\u8bd1\u4ef7\u503c\u7684\u4ee3\u7801&#xff0c;\u89e6\u53d1\u5373\u65f6\u7f16\u8bd1&#xff08;JIT&#xff09;\u6216\u6808\u4e0a\u66ff\u6362&#xff1b;\u7f16\u8bd1\u5668\u4e0e\u89e3\u91ca\u5668\u534f\u540c\u5de5\u4f5c&#xff0c;\u5728\u7a0b\u5e8f\u54cd\u5e94\u65f6\u95f4\u548c\u6267\u884c\u6027\u80fd\u95f4\u53d6\u5f97\u6700\u4f73\u5e73\u8861\u3002<\/li>\n<li>\u5e94\u7528\u573a\u666f&#xff1a;Sun\/Oracle JDK \u548c OpenJDK \u7684\u9ed8\u8ba4\u865a\u62df\u673a&#xff0c;\u8986\u76d6\u670d\u52a1\u5668\u3001\u684c\u9762\u3001\u79fb\u52a8\u7aef\u3001\u5d4c\u5165\u5f0f\u7b49\u5168\u573a\u666f\u3002<\/li>\n<\/ul>\n<h4 id=\"4.%20JRockit%EF%BC%88%E4%B8%93%E6%B3%A8%E6%9C%8D%E5%8A%A1%E5%99%A8%E7%AB%AF%EF%BC%89\">4. JRockit&#xff08;\u4e13\u6ce8\u670d\u52a1\u5668\u7aef&#xff09;<\/h4>\n<ul>\n<li>\u6838\u5fc3\u5b9a\u4f4d&#xff1a;\u4e13\u4e3a\u670d\u52a1\u5668\u7aef\u5e94\u7528\u4f18\u5316&#xff0c;\u4e0d\u5173\u6ce8\u542f\u52a8\u901f\u5ea6&#xff0c;\u4ec5\u4fdd\u7559 JIT \u7f16\u8bd1\u5668&#xff0c;\u65e0\u89e3\u91ca\u5668\u5b9e\u73b0&#xff0c;\u6240\u6709\u4ee3\u7801\u5747\u901a\u8fc7 JIT \u7f16\u8bd1\u540e\u6267\u884c\u3002<\/li>\n<li>\u6838\u5fc3\u4f18\u52bf&#xff1a;\u8fd0\u884c\u901f\u5ea6\u5feb&#xff0c;\u88ab\u79f0\u4e3a \u201c\u4e16\u754c\u4e0a\u6700\u5feb\u7684 JVM\u201d&#xff0c;\u90e8\u5206\u573a\u666f\u6027\u80fd\u63d0\u5347\u8d85 70%&#xff1b;\u63d0\u4f9b JRockit Real Time&#xff08;\u9762\u5411\u5ef6\u8fdf\u654f\u611f\u578b\u5e94\u7528&#xff0c;\u54cd\u5e94\u65f6\u95f4\u8fbe\u6beb\u79d2 \/ \u5fae\u79d2\u7ea7&#xff09;\u548c MissionControl&#xff08;\u4f4e\u5f00\u9500\u76d1\u63a7\u5206\u6790\u5de5\u5177&#xff09;\u3002<\/li>\n<li>\u547d\u8fd0&#xff1a;2008 \u5e74\u968f BEA \u88ab Oracle \u6536\u8d2d&#xff0c;Oracle \u5728 JDK8 \u4e2d\u5b8c\u6210\u5176\u4e0e HotSpot \u7684\u6574\u5408&#xff0c;\u5c06 JRockit \u7684\u4f18\u79c0\u7279\u6027\u79fb\u690d\u5230 HotSpot \u4e2d\u3002<\/li>\n<\/ul>\n<h4 id=\"5.%20J9%20VM%EF%BC%88IBM%EF%BC%89\">5. J9 VM&#xff08;IBM&#xff09;<\/h4>\n<ul>\n<li>\u5168\u79f0&#xff1a;IBM Technology for Java Virtual Machine&#xff08;IT4J&#xff09;&#xff0c;\u5185\u90e8\u4ee3\u53f7 J9\u3002<\/li>\n<li>\u6838\u5fc3\u5b9a\u4f4d&#xff1a;\u4e0e HotSpot \u7c7b\u4f3c&#xff0c;\u662f\u591a\u7528\u9014 JVM&#xff0c;\u9002\u7528\u4e8e\u670d\u52a1\u5668\u7aef\u3001\u684c\u9762\u5e94\u7528\u3001\u5d4c\u5165\u5f0f\u7b49\u573a\u666f&#xff0c;\u5e7f\u6cdb\u7528\u4e8e IBM \u7684\u5404\u7c7b Java \u4ea7\u54c1\u3002<\/li>\n<li>\u6838\u5fc3\u4f18\u52bf&#xff1a;\u53f7\u79f0 \u201c\u4e16\u754c\u4e0a\u6700\u5feb\u7684 Java \u865a\u62df\u673a\u201d&#xff0c;\u5728 IBM \u81ea\u6709\u4ea7\u54c1\u4e0a\u7a33\u5b9a\u6027\u6781\u5f3a\u3002<\/li>\n<li>\u547d\u8fd0&#xff1a;2017 \u5e74 IBM \u5c06\u5176\u5f00\u6e90&#xff0c;\u547d\u540d\u4e3a OpenJ9&#xff0c;\u4ea4\u7531 Eclipse \u57fa\u91d1\u4f1a\u7ba1\u7406&#xff0c;\u66f4\u540d\u4e3a Eclipse OpenJ9\u3002<\/li>\n<\/ul>\n<h4 id=\"6.%20Taobao%20JVM%EF%BC%88%E5%9B%BD%E4%BA%A7%E6%B7%B1%E5%BA%A6%E5%AE%9A%E5%88%B6%EF%BC%89\">6. Taobao JVM&#xff08;\u56fd\u4ea7\u6df1\u5ea6\u5b9a\u5236&#xff09;<\/h4>\n<ul>\n<li>\u7814\u53d1\u80cc\u666f&#xff1a;\u7531\u963f\u91cc AliJVM \u56e2\u961f\u57fa\u4e8e OpenJDK HotSpot \u5f00\u53d1&#xff0c;\u662f\u56fd\u5185\u9996\u4e2a\u5f00\u6e90\u7684\u9ad8\u6027\u80fd\u670d\u52a1\u5668\u7ea7 JVM&#xff0c;\u4e3a\u963f\u91cc\u4e91\u8ba1\u7b97\u3001\u91d1\u878d\u3001\u7535\u5546\u7b49\u9ad8\u5e76\u53d1\u573a\u666f\u91cf\u8eab\u5b9a\u5236\u3002<\/li>\n<li>\u6838\u5fc3\u7279\u6027&#xff1a;\n<li>GCIH&#xff08;GC invisible heap&#xff09;\u6280\u672f&#xff1a;\u5b9e\u73b0 \u201c\u5806\u5916\u5b58\u50a8\u201d&#xff0c;\u5c06\u957f\u751f\u547d\u5468\u671f\u5bf9\u8c61\u79fb\u81f3\u5806\u5916&#xff0c;GC \u65e0\u6cd5\u7ba1\u7406&#xff0c;\u964d\u4f4e GC \u56de\u6536\u9891\u7387\u3001\u63d0\u5347\u56de\u6536\u6548\u7387\u3002<\/li>\n<li>\u8de8\u8fdb\u7a0b\u5bf9\u8c61\u5171\u4eab&#xff1a;GCIH \u4e2d\u7684\u5bf9\u8c61\u53ef\u5728\u591a\u4e2a JVM \u8fdb\u7a0b\u95f4\u5171\u4eab&#xff0c;\u8282\u7701\u5185\u5b58\u5f00\u9500\u3002<\/li>\n<li>\u4f18\u5316 JNI \u8c03\u7528&#xff1a;\u901a\u8fc7 crc32 \u6307\u4ee4\u5b9e\u73b0 JVM intrinsic&#xff0c;\u964d\u4f4e JNI \u8c03\u7528\u5f00\u9500\u3002<\/li>\n<li>\u786c\u4ef6\u9002\u914d&#xff1a;\u9488\u5bf9 Intel CPU \u4f18\u5316&#xff0c;\u727a\u7272\u90e8\u5206\u517c\u5bb9\u6027\u6362\u53d6\u6781\u81f4\u6027\u80fd\u3002<\/li>\n<li>ZenGC&#xff1a;\u4e13\u4e3a\u5927\u6570\u636e\u573a\u666f\u8bbe\u8ba1\u7684\u5783\u573e\u6536\u96c6\u5668\u3002<\/li>\n<\/li>\n<li>\u5e94\u7528\u573a\u666f&#xff1a;\u5df2\u5168\u9762\u5e94\u7528\u4e8e\u6dd8\u5b9d\u3001\u5929\u732b\u7b49\u963f\u91cc\u6838\u5fc3\u4ea7\u54c1&#xff0c;\u66ff\u6362\u4e86 Oracle \u5b98\u65b9 JVM\u3002<\/li>\n<\/ul>\n<h4 id=\"%E5%85%B3%E9%94%AE%E8%A1%A5%E5%85%85%EF%BC%9AJVM%20%E4%B8%8E%E3%80%8AJava%20%E8%99%9A%E6%8B%9F%E6%9C%BA%E8%A7%84%E8%8C%83%E3%80%8B\">\u5173\u952e\u8865\u5145&#xff1a;JVM \u4e0e\u300aJava \u865a\u62df\u673a\u89c4\u8303\u300b<\/h4>\n<p>\u4e0a\u8ff0\u6240\u6709 JVM \u5b9e\u73b0&#xff08;HotSpot\u3001J9\u3001Taobao JVM \u7b49&#xff09;\u5747\u9700\u9075\u5faa\u300aJava \u865a\u62df\u673a\u89c4\u8303\u300b\u2014\u2014Oracle \u53d1\u5e03\u7684 Java \u9886\u57df\u6743\u5a01\u8457\u4f5c&#xff0c;\u8be6\u7ec6\u5b9a\u4e49\u4e86 JVM \u7684\u7ec4\u6210\u3001\u6307\u4ee4\u96c6\u3001\u5185\u5b58\u6a21\u578b\u7b49\u6838\u5fc3\u89c4\u8303&#xff0c;\u786e\u4fdd\u4e0d\u540c\u5382\u5546\u7684 JVM \u80fd\u6b63\u786e\u6267\u884c Java \u5b57\u8282\u7801\u3002\u672c\u6587\u540e\u7eed\u5185\u5bb9\u5747\u4ee5 HotSpot&#xff08;Oracle JDK \u9ed8\u8ba4\u865a\u62df\u673a&#xff09;\u4e3a\u6838\u5fc3\u5c55\u5f00\u3002<\/p>\n<h3 id=\"%E4%B8%89%E3%80%81JVM%20%E6%89%A7%E8%A1%8C%E6%B5%81%E7%A8%8B\">\u4e09\u3001JVM \u6267\u884c\u6d41\u7a0b<\/h3>\n<p>JVM \u7684\u6838\u5fc3\u804c\u8d23\u662f\u5c06 Java \u5b57\u8282\u7801\u8f6c\u6362\u4e3a\u5e95\u5c42\u7cfb\u7edf\u6307\u4ee4\u5e76\u6267\u884c&#xff0c;\u5b8c\u6574\u6d41\u7a0b\u6d89\u53ca\u56db\u5927\u6838\u5fc3\u7ec4\u4ef6&#xff0c;\u6267\u884c\u6b65\u9aa4\u5982\u4e0b&#xff1a;<\/p>\n<h4 id=\"1.%20%E6%A0%B8%E5%BF%83%E7%BB%84%E4%BB%B6\">1. \u6838\u5fc3\u7ec4\u4ef6<\/h4>\n<ul>\n<li>\u7c7b\u52a0\u8f7d\u5668&#xff08;ClassLoader&#xff09;&#xff1a;\u8d1f\u8d23\u52a0\u8f7d\u5b57\u8282\u7801\u6587\u4ef6&#xff08;.class&#xff09;\u5230\u5185\u5b58\u3002<\/li>\n<li>\u8fd0\u884c\u65f6\u6570\u636e\u533a&#xff08;Runtime Data Area&#xff09;&#xff1a;\u5b58\u50a8\u7c7b\u4fe1\u606f\u3001\u5bf9\u8c61\u5b9e\u4f8b\u3001\u7ebf\u7a0b\u72b6\u6001\u7b49\u6570\u636e\u3002<\/li>\n<li>\u6267\u884c\u5f15\u64ce&#xff08;Execution Engine&#xff09;&#xff1a;\u5c06\u5b57\u8282\u7801\u7ffb\u8bd1\u4e3a\u5e95\u5c42\u7cfb\u7edf\u6307\u4ee4&#xff0c;\u4ea4\u7531 CPU \u6267\u884c\u3002<\/li>\n<li>\u672c\u5730\u5e93\u63a5\u53e3&#xff08;Native Interface&#xff09;&#xff1a;\u8c03\u7528 C\/C&#043;&#043; \u7b49\u672c\u5730\u65b9\u6cd5\u5e93&#xff0c;\u5b9e\u73b0 Java \u65e0\u6cd5\u76f4\u63a5\u5b8c\u6210\u7684\u5e95\u5c42\u529f\u80fd&#xff08;\u5982\u64cd\u4f5c\u7cfb\u7edf\u4ea4\u4e92\u3001\u786c\u4ef6\u64cd\u4f5c&#xff09;\u3002<\/li>\n<\/ul>\n<h4 id=\"2.%20%E5%AE%8C%E6%95%B4%E6%89%A7%E8%A1%8C%E6%B5%81%E7%A8%8B\">2. \u5b8c\u6574\u6267\u884c\u6d41\u7a0b<\/h4>\n<li>\u7f16\u8bd1&#xff1a;Java \u6e90\u4ee3\u7801&#xff08;.java&#xff09;\u901a\u8fc7 javac \u7f16\u8bd1\u5668\u7f16\u8bd1\u4e3a\u5b57\u8282\u7801\u6587\u4ef6&#xff08;.class&#xff09;&#xff0c;\u5b57\u8282\u7801\u662f JVM \u7684\u6307\u4ee4\u96c6\u89c4\u8303&#xff0c;\u4e0d\u4f9d\u8d56\u5e95\u5c42\u64cd\u4f5c\u7cfb\u7edf\u3002<\/li>\n<li>\u52a0\u8f7d&#xff1a;\u7c7b\u52a0\u8f7d\u5668\u6839\u636e\u7c7b\u7684\u5168\u9650\u5b9a\u540d&#xff0c;\u8bfb\u53d6\u5b57\u8282\u7801\u6587\u4ef6&#xff0c;\u5c06\u5176\u8f6c\u6362\u4e3a\u65b9\u6cd5\u533a\u7684\u8fd0\u884c\u65f6\u6570\u636e\u7ed3\u6784&#xff0c;\u5e76\u5728\u5185\u5b58\u4e2d\u751f\u6210\u4ee3\u8868\u8be5\u7c7b\u7684 java.lang.Class \u5bf9\u8c61&#xff08;\u8bbf\u95ee\u5165\u53e3&#xff09;\u3002<\/li>\n<li>\u5b58\u50a8&#xff1a;\u7c7b\u4fe1\u606f\u3001\u9759\u6001\u53d8\u91cf\u3001\u5e38\u91cf\u7b49\u5b58\u5165\u65b9\u6cd5\u533a&#xff1b;\u5bf9\u8c61\u5b9e\u4f8b\u5b58\u5165\u5806&#xff1b;\u7ebf\u7a0b\u6267\u884c\u65b9\u6cd5\u65f6&#xff0c;\u751f\u6210\u6808\u5e27\u5b58\u5165\u865a\u62df\u673a\u6808&#xff1b;\u672c\u5730\u65b9\u6cd5\u6267\u884c\u65f6\u4f7f\u7528\u672c\u5730\u65b9\u6cd5\u6808&#xff1b;\u7a0b\u5e8f\u8ba1\u6570\u5668\u8bb0\u5f55\u7ebf\u7a0b\u6267\u884c\u4f4d\u7f6e\u3002<\/li>\n<li>\u6267\u884c&#xff1a;\u6267\u884c\u5f15\u64ce\u901a\u8fc7\u89e3\u91ca\u5668\u6216 JIT \u7f16\u8bd1\u5668&#xff0c;\u5c06\u5b57\u8282\u7801\u7ffb\u8bd1\u4e3a CPU \u53ef\u6267\u884c\u7684\u673a\u5668\u6307\u4ee4&#xff1b;\u82e5\u6d89\u53ca\u5e95\u5c42\u64cd\u4f5c&#xff08;\u5982\u6587\u4ef6 IO&#xff09;&#xff0c;\u901a\u8fc7\u672c\u5730\u5e93\u63a5\u53e3\u8c03\u7528\u672c\u5730\u65b9\u6cd5\u5e93\u5b8c\u6210\u3002<\/li>\n<li>\u6536\u5c3e&#xff1a;\u7a0b\u5e8f\u6267\u884c\u5b8c\u6bd5\u540e&#xff0c;\u5783\u573e\u6536\u96c6\u5668\u56de\u6536\u5806\u4e2d\u65e0\u7528\u5bf9\u8c61&#xff0c;\u7ebf\u7a0b\u7ec8\u6b62\u540e\u91ca\u653e\u865a\u62df\u673a\u6808\u3001\u672c\u5730\u65b9\u6cd5\u6808\u7b49\u7ebf\u7a0b\u79c1\u6709\u8d44\u6e90\u3002<\/li>\n<h3 id=\"%E5%9B%9B%E3%80%81%E8%BF%90%E8%A1%8C%E6%97%B6%E6%95%B0%E6%8D%AE%E5%8C%BA%EF%BC%88%E5%86%85%E5%AD%98%E5%B8%83%E5%B1%80%EF%BC%89\">\u56db\u3001\u8fd0\u884c\u65f6\u6570\u636e\u533a&#xff08;\u5185\u5b58\u5e03\u5c40&#xff09;<\/h3>\n<p>\u8fd0\u884c\u65f6\u6570\u636e\u533a\u662f JVM \u5728\u8fd0\u884c\u8fc7\u7a0b\u4e2d\u5206\u914d\u548c\u7ba1\u7406\u5185\u5b58\u7684\u533a\u57df&#xff0c;\u4e0e \u201cJava \u5185\u5b58\u6a21\u578b&#xff08;JMM&#xff09;\u201d \u662f\u5b8c\u5168\u4e0d\u540c\u7684\u6982\u5ff5 \u2014\u2014 \u524d\u8005\u662f JVM \u7684\u7269\u7406\u5185\u5b58\u5212\u5206&#xff0c;\u540e\u8005\u662f\u5e76\u53d1\u7f16\u7a0b\u7684\u5185\u5b58\u8bbf\u95ee\u89c4\u8303\u3002\u8fd0\u884c\u65f6\u6570\u636e\u533a\u5206\u4e3a 5 \u4e2a\u90e8\u5206&#xff0c;\u6309 \u201c\u7ebf\u7a0b\u5171\u4eab \/ \u79c1\u6709\u201d \u53ef\u5206\u4e3a\u4e24\u7c7b&#xff1a;<\/p>\n<table>\n<tr>\u7c7b\u578b\u5305\u542b\u533a\u57df\u6838\u5fc3\u7279\u70b9<\/tr>\n<tbody>\n<tr>\n<td>\u7ebf\u7a0b\u5171\u4eab<\/td>\n<td>\u5806\u3001\u65b9\u6cd5\u533a&#xff08;\u5143\u7a7a\u95f4&#xff09;<\/td>\n<td>\u6240\u6709\u7ebf\u7a0b\u5171\u7528&#xff0c;\u751f\u547d\u5468\u671f\u4e0e JVM \u4e00\u81f4&#xff0c;\u9700\u5783\u573e\u56de\u6536<\/td>\n<\/tr>\n<tr>\n<td>\u7ebf\u7a0b\u79c1\u6709<\/td>\n<td>\u865a\u62df\u673a\u6808\u3001\u672c\u5730\u65b9\u6cd5\u6808\u3001\u7a0b\u5e8f\u8ba1\u6570\u5668<\/td>\n<td>\u6bcf\u4e2a\u7ebf\u7a0b\u72ec\u7acb\u62e5\u6709&#xff0c;\u751f\u547d\u5468\u671f\u4e0e\u7ebf\u7a0b\u4e00\u81f4&#xff0c;\u65e0\u9700\u5783\u573e\u56de\u6536<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h4 id=\"1.%20%E5%A0%86%EF%BC%88%E7%BA%BF%E7%A8%8B%E5%85%B1%E4%BA%AB%EF%BC%89\">1. \u5806&#xff08;\u7ebf\u7a0b\u5171\u4eab&#xff09;<\/h4>\n<ul>\n<li>\u6838\u5fc3\u4f5c\u7528&#xff1a;\u5b58\u50a8 Java \u7a0b\u5e8f\u4e2d\u521b\u5efa\u7684\u6240\u6709\u5bf9\u8c61\u5b9e\u4f8b&#xff08;\u5305\u62ec\u6570\u7ec4&#xff09;&#xff0c;\u662f JVM \u5185\u5b58\u4e2d\u6700\u5927\u7684\u533a\u57df&#xff0c;\u4e5f\u662f\u5783\u573e\u56de\u6536\u7684\u4e3b\u8981\u76ee\u6807\u3002<\/li>\n<li>\u5185\u5b58\u53c2\u6570&#xff1a;\u901a\u8fc7 JVM \u53c2\u6570\u914d\u7f6e\u5927\u5c0f&#xff0c;-Xms\u6307\u5b9a\u6700\u5c0f\u542f\u52a8\u5185\u5b58&#xff0c;-Xmx\u6307\u5b9a\u6700\u5927\u8fd0\u884c\u5185\u5b58&#xff08;\u5982-Xms20m -Xmx20m\u8868\u793a\u5806\u5185\u5b58\u56fa\u5b9a\u4e3a 20MB&#xff09;\u3002<\/li>\n<li>\u533a\u57df\u5212\u5206&#xff1a;\n<ul>\n<li>\u65b0\u751f\u4ee3&#xff08;Young \u533a&#xff09;&#xff1a;\u5b58\u50a8\u65b0\u5efa\u5bf9\u8c61&#xff0c;\u5206\u4e3a 1 \u4e2a Eden \u533a\u548c 2 \u4e2a Survivor \u533a&#xff08;S0\/S1&#xff0c;\u4e5f\u53eb From\/To \u533a&#xff09;&#xff0c;\u9ed8\u8ba4\u6bd4\u4f8b\u4e3a Eden:S0:S1&#061;8:1:1\u3002<\/li>\n<li>\u8001\u5e74\u4ee3&#xff08;Old \u533a&#xff09;&#xff1a;\u5b58\u50a8\u7ecf\u8fc7\u591a\u6b21\u5783\u573e\u56de\u6536\u540e\u4ecd\u5b58\u6d3b\u7684\u5bf9\u8c61\u3001\u5927\u5bf9\u8c61&#xff08;\u8d85\u8fc7\u65b0\u751f\u4ee3\u9608\u503c\u7684\u5bf9\u8c61&#xff09;\u3002<\/li>\n<\/ul>\n<\/li>\n<li>\u5783\u573e\u56de\u6536\u903b\u8f91&#xff1a;\u65b0\u751f\u4ee3\u89e6\u53d1 Minor GC&#xff08;\u590d\u5236\u7b97\u6cd5&#xff09;&#xff0c;\u8001\u5e74\u4ee3\u89e6\u53d1 Full GC&#xff08;\u6807\u8bb0 &#8211; \u6574\u7406\u7b97\u6cd5&#xff09;&#xff1b;Minor GC \u65f6&#xff0c;Eden \u533a\u5b58\u6d3b\u5bf9\u8c61\u590d\u5236\u5230\u7a7a\u95f2\u7684 Survivor \u533a&#xff0c;\u6e05\u7406 Eden \u548c\u5df2\u4f7f\u7528\u7684 Survivor \u533a&#xff1b;\u5bf9\u8c61\u5728 Survivor \u533a\u590d\u5236\u6b21\u6570\u8fbe\u5230\u9608\u503c&#xff08;\u9ed8\u8ba4 15 \u6b21&#xff0c;\u7531MaxTenuringThreshold\u53c2\u6570\u63a7\u5236&#xff09;\u540e&#xff0c;\u664b\u5347\u5230\u8001\u5e74\u4ee3\u3002<\/li>\n<\/ul>\n<h4 id=\"2.%20%E8%99%9A%E6%8B%9F%E6%9C%BA%E6%A0%88%EF%BC%88%E7%BA%BF%E7%A8%8B%E7%A7%81%E6%9C%89%EF%BC%89\">2. \u865a\u62df\u673a\u6808&#xff08;\u7ebf\u7a0b\u79c1\u6709&#xff09;<\/h4>\n<ul>\n<li>\u6838\u5fc3\u4f5c\u7528&#xff1a;\u63cf\u8ff0 Java \u65b9\u6cd5\u7684\u6267\u884c\u5185\u5b58\u6a21\u578b&#xff0c;\u6bcf\u4e2a\u65b9\u6cd5\u6267\u884c\u65f6\u90fd\u4f1a\u521b\u5efa\u4e00\u4e2a \u201c\u6808\u5e27\u201d&#xff0c;\u6808\u5e27\u5165\u6808&#xff08;\u65b9\u6cd5\u8c03\u7528&#xff09;\u548c\u51fa\u6808&#xff08;\u65b9\u6cd5\u8fd4\u56de&#xff09;\u7684\u8fc7\u7a0b\u5373\u65b9\u6cd5\u7684\u6267\u884c\u8fc7\u7a0b\u3002<\/li>\n<li>\u751f\u547d\u5468\u671f&#xff1a;\u4e0e\u7ebf\u7a0b\u4e00\u81f4&#xff0c;\u7ebf\u7a0b\u542f\u52a8\u65f6\u521b\u5efa&#xff0c;\u7ebf\u7a0b\u7ec8\u6b62\u65f6\u9500\u6bc1&#xff0c;\u4e0d\u5b58\u5728\u7ebf\u7a0b\u5b89\u5168\u95ee\u9898\u3002<\/li>\n<li>\u6808\u5e27\u7ec4\u6210&#xff1a;\n<li>\u5c40\u90e8\u53d8\u91cf\u8868&#xff1a;\u5b58\u50a8\u65b9\u6cd5\u53c2\u6570\u548c\u5c40\u90e8\u53d8\u91cf&#xff0c;\u5305\u542b 8 \u5927\u57fa\u672c\u6570\u636e\u7c7b\u578b\u3001\u5bf9\u8c61\u5f15\u7528&#xff08;\u5730\u5740\u6307\u9488&#xff09;&#xff0c;\u5185\u5b58\u7a7a\u95f4\u5728\u7f16\u8bd1\u671f\u95f4\u786e\u5b9a&#xff0c;\u6267\u884c\u65f6\u4e0d\u53ef\u4fee\u6539\u3002<\/li>\n<li>\u64cd\u4f5c\u6570\u6808&#xff1a;\u65b9\u6cd5\u6267\u884c\u65f6\u7684\u4e34\u65f6\u6570\u636e\u5b58\u50a8\u533a&#xff0c;\u901a\u8fc7\u5165\u6808\u3001\u51fa\u6808\u64cd\u4f5c\u5b8c\u6210\u8fd0\u7b97&#xff08;\u5982a&#043;b\u9700\u5148\u5c06 a\u3001b \u5165\u6808&#xff0c;\u6267\u884c\u52a0\u6cd5\u540e\u5c06\u7ed3\u679c\u5165\u6808&#xff09;\u3002<\/li>\n<li>\u52a8\u6001\u8fde\u63a5&#xff1a;\u6307\u5411\u8fd0\u884c\u65f6\u5e38\u91cf\u6c60\u7684\u65b9\u6cd5\u5f15\u7528&#xff0c;\u7528\u4e8e\u5c06\u7b26\u53f7\u5f15\u7528\u8f6c\u6362\u4e3a\u76f4\u63a5\u5f15\u7528&#xff08;\u652f\u6301\u65b9\u6cd5\u91cd\u5199\u7b49\u52a8\u6001\u7279\u6027&#xff09;\u3002<\/li>\n<li>\u65b9\u6cd5\u8fd4\u56de\u5730\u5740&#xff1a;\u5b58\u50a8\u65b9\u6cd5\u6267\u884c\u5b8c\u6bd5\u540e\u8fd4\u56de\u7684 PC \u5bc4\u5b58\u5668\u5730\u5740&#xff0c;\u786e\u4fdd\u7ebf\u7a0b\u80fd\u6062\u590d\u5230\u4e4b\u524d\u7684\u6267\u884c\u4f4d\u7f6e\u3002<\/li>\n<\/li>\n<li>\u5173\u952e\u6982\u5ff5&#xff1a;\u201c\u7ebf\u7a0b\u79c1\u6709\u201d \u6307\u6bcf\u4e2a\u7ebf\u7a0b\u62e5\u6709\u72ec\u7acb\u7684\u865a\u62df\u673a\u6808&#xff0c;\u7ebf\u7a0b\u5207\u6362\u65f6\u65e0\u9700\u62c5\u5fc3\u6808\u6570\u636e\u51b2\u7a81&#xff0c;\u56e0\u4e3a\u5904\u7406\u5668\u540c\u4e00\u65f6\u523b\u4ec5\u6267\u884c\u4e00\u6761\u7ebf\u7a0b\u7684\u6307\u4ee4\u3002<\/li>\n<\/ul>\n<h4 id=\"3.%20%E6%9C%AC%E5%9C%B0%E6%96%B9%E6%B3%95%E6%A0%88%EF%BC%88%E7%BA%BF%E7%A8%8B%E7%A7%81%E6%9C%89%EF%BC%89\">3. \u672c\u5730\u65b9\u6cd5\u6808&#xff08;\u7ebf\u7a0b\u79c1\u6709&#xff09;<\/h4>\n<ul>\n<li>\u6838\u5fc3\u4f5c\u7528&#xff1a;\u4e0e\u865a\u62df\u673a\u6808\u529f\u80fd\u7c7b\u4f3c&#xff0c;\u533a\u522b\u5728\u4e8e\u865a\u62df\u673a\u6808\u4e3a Java \u65b9\u6cd5\u670d\u52a1&#xff0c;\u672c\u5730\u65b9\u6cd5\u6808\u4e3a Native \u65b9\u6cd5&#xff08;\u7531 C\/C&#043;&#043; \u5b9e\u73b0&#xff0c;\u88ab Java \u8c03\u7528\u7684\u65b9\u6cd5&#xff09;\u670d\u52a1\u3002<\/li>\n<li>\u751f\u547d\u5468\u671f&#xff1a;\u4e0e\u7ebf\u7a0b\u4e00\u81f4&#xff0c;\u7ebf\u7a0b\u7ec8\u6b62\u65f6\u9500\u6bc1\u3002<\/li>\n<li>\u5f02\u5e38&#xff1a;\u82e5\u672c\u5730\u65b9\u6cd5\u6267\u884c\u65f6\u6808\u6df1\u5ea6\u8d85\u8fc7\u9650\u5236&#xff0c;\u4f1a\u629b\u51fa StackOverflowError&#xff1b;\u82e5\u6269\u5c55\u6808\u65f6\u65e0\u6cd5\u7533\u8bf7\u5230\u8db3\u591f\u5185\u5b58&#xff0c;\u4f1a\u629b\u51fa OutOfMemoryError\u3002<\/li>\n<\/ul>\n<h4 id=\"4.%20%E7%A8%8B%E5%BA%8F%E8%AE%A1%E6%95%B0%E5%99%A8%EF%BC%88%E7%BA%BF%E7%A8%8B%E7%A7%81%E6%9C%89%EF%BC%89\">4. \u7a0b\u5e8f\u8ba1\u6570\u5668&#xff08;\u7ebf\u7a0b\u79c1\u6709&#xff09;<\/h4>\n<ul>\n<li>\u6838\u5fc3\u4f5c\u7528&#xff1a;\u8bb0\u5f55\u5f53\u524d\u7ebf\u7a0b\u6267\u884c\u7684\u5b57\u8282\u7801\u884c\u53f7\u6307\u793a\u5668&#xff0c;\u76f8\u5f53\u4e8e\u7ebf\u7a0b\u7684 \u201c\u6267\u884c\u8fdb\u5ea6\u6761\u201d\u3002<\/li>\n<li>\u5177\u4f53\u903b\u8f91&#xff1a;\n<ul>\n<li>\u82e5\u7ebf\u7a0b\u6267\u884c Java \u65b9\u6cd5&#xff0c;\u8ba1\u6570\u5668\u5b58\u50a8\u5f53\u524d\u6267\u884c\u7684\u5b57\u8282\u7801\u6307\u4ee4\u5730\u5740\u3002<\/li>\n<li>\u82e5\u7ebf\u7a0b\u6267\u884c Native \u65b9\u6cd5&#xff0c;\u8ba1\u6570\u5668\u503c\u4e3a\u7a7a&#xff08;Undefined&#xff09;\u3002<\/li>\n<\/ul>\n<\/li>\n<li>\u6838\u5fc3\u7279\u70b9&#xff1a;JVM \u89c4\u8303\u4e2d\u552f\u4e00\u6ca1\u6709\u89c4\u5b9a OutOfMemoryError \u7684\u533a\u57df \u2014\u2014 \u5185\u5b58\u5360\u7528\u6781\u5c0f&#xff0c;\u4e14\u751f\u547d\u5468\u671f\u4e0e\u7ebf\u7a0b\u4e00\u81f4&#xff0c;\u65e0\u9700\u989d\u5916\u5185\u5b58\u5206\u914d\u3002<\/li>\n<\/ul>\n<h4 id=\"5.%20%E6%96%B9%E6%B3%95%E5%8C%BA%EF%BC%88%E7%BA%BF%E7%A8%8B%E5%85%B1%E4%BA%AB%EF%BC%89\">5. \u65b9\u6cd5\u533a&#xff08;\u7ebf\u7a0b\u5171\u4eab&#xff09;<\/h4>\n<ul>\n<li>\u6838\u5fc3\u4f5c\u7528&#xff1a;\u5b58\u50a8\u88ab\u865a\u62df\u673a\u52a0\u8f7d\u7684\u7c7b\u4fe1\u606f&#xff08;\u7c7b\u540d\u3001\u7236\u7c7b\u3001\u63a5\u53e3\u3001\u5b57\u6bb5\u3001\u65b9\u6cd5&#xff09;\u3001\u5e38\u91cf\u3001\u9759\u6001\u53d8\u91cf\u3001\u5373\u65f6\u7f16\u8bd1\u5668\u7f16\u8bd1\u540e\u7684\u4ee3\u7801\u7b49\u6570\u636e\u3002<\/li>\n<li>\u5b9e\u73b0\u5dee\u5f02&#xff1a;\n<ul>\n<li>JDK7 \u53ca\u4e4b\u524d&#xff1a;\u79f0\u4e3a \u201c\u6c38\u4e45\u4ee3&#xff08;PermGen&#xff09;\u201d&#xff0c;\u5c5e\u4e8e JVM \u5185\u5b58\u7684\u4e00\u90e8\u5206&#xff0c;\u5927\u5c0f\u901a\u8fc7-XX:PermSize\u548c-XX:MaxPermSize\u914d\u7f6e\u3002<\/li>\n<li>JDK8 \u53ca\u4e4b\u540e&#xff1a;\u6539\u4e3a \u201c\u5143\u7a7a\u95f4&#xff08;Metaspace&#xff09;\u201d&#xff0c;\u4f7f\u7528\u672c\u5730\u5185\u5b58&#xff08;\u64cd\u4f5c\u7cfb\u7edf\u5185\u5b58&#xff09;&#xff0c;\u5927\u5c0f\u4e0d\u518d\u53d7 JVM \u5185\u5b58\u9650\u5236&#xff0c;\u4ec5\u53d7\u672c\u5730\u5185\u5b58\u5927\u5c0f\u7ea6\u675f\u3002<\/li>\n<\/ul>\n<\/li>\n<li>\u5173\u952e\u53d8\u5316&#xff08;JDK8&#xff09;&#xff1a;\n<li>\u5b57\u7b26\u4e32\u5e38\u91cf\u6c60\u4ece\u6c38\u4e45\u4ee3\u79fb\u81f3\u5806\u4e2d&#xff08;\u51cf\u5c11\u6c38\u4e45\u4ee3\u5185\u5b58\u6ea2\u51fa\u98ce\u9669&#xff09;\u3002<\/li>\n<li>\u9759\u6001\u53d8\u91cf\u3001\u7c7b\u5143\u4fe1\u606f\u4ecd\u5b58\u50a8\u5728\u5143\u7a7a\u95f4\u3002<\/li>\n<\/li>\n<li>\u8fd0\u884c\u65f6\u5e38\u91cf\u6c60&#xff1a;\u65b9\u6cd5\u533a\u7684\u4e00\u90e8\u5206&#xff0c;\u5b58\u50a8\u5b57\u9762\u91cf&#xff08;\u5b57\u7b26\u4e32\u3001final \u5e38\u91cf\u3001\u57fa\u672c\u6570\u636e\u7c7b\u578b\u503c&#xff09;\u548c\u7b26\u53f7\u5f15\u7528&#xff08;\u7c7b\u5168\u9650\u5b9a\u540d\u3001\u5b57\u6bb5 \/ \u65b9\u6cd5\u540d\u79f0\u53ca\u63cf\u8ff0\u7b26&#xff09;&#xff0c;\u662f\u5b57\u8282\u7801\u6587\u4ef6\u4e2d \u201c\u5e38\u91cf\u6c60\u8868\u201d \u7684\u8fd0\u884c\u65f6\u4f53\u73b0\u3002<\/li>\n<\/ul>\n<h4 id=\"6.%20%E5%86%85%E5%AD%98%E6%BA%A2%E5%87%BA%E5%BC%82%E5%B8%B8%EF%BC%88OOM%EF%BC%89%E8%AF%A6%E8%A7%A3\">6. \u5185\u5b58\u6ea2\u51fa\u5f02\u5e38&#xff08;OOM&#xff09;\u8be6\u89e3<\/h4>\n<p>\u8fd0\u884c\u65f6\u6570\u636e\u533a\u7684\u5404\u533a\u57df\u5747\u53ef\u80fd\u51fa\u73b0\u5185\u5b58\u6ea2\u51fa&#xff0c;\u4e0d\u540c\u533a\u57df\u7684\u5f02\u5e38\u573a\u666f\u548c\u6392\u67e5\u65b9\u5f0f\u4e0d\u540c&#xff1a;<\/p>\n<h5 id=\"%EF%BC%881%EF%BC%89Java%20%E5%A0%86%E6%BA%A2%E5%87%BA%EF%BC%88java.lang.OutOfMemoryError%3A%20Java%20heap%20space%EF%BC%89\">&#xff08;1&#xff09;Java \u5806\u6ea2\u51fa&#xff08;java.lang.OutOfMemoryError: Java heap space&#xff09;<\/h5>\n<ul>\n<li>\u89e6\u53d1\u6761\u4ef6&#xff1a;\u4e0d\u65ad\u521b\u5efa\u5bf9\u8c61&#xff0c;\u4e14 GC Roots \u5230\u5bf9\u8c61\u5b58\u5728\u53ef\u8fbe\u8def\u5f84&#xff08;\u907f\u514d\u88ab GC \u56de\u6536&#xff09;&#xff0c;\u5f53\u5bf9\u8c61\u6570\u91cf\u8d85\u8fc7\u5806\u6700\u5927\u5bb9\u91cf\u65f6\u89e6\u53d1\u3002<\/li>\n<li>\u6d4b\u8bd5\u914d\u7f6e&#xff1a;JVM \u53c2\u6570-Xmx20m -Xms20m -XX:&#043;HeapDumpOnOutOfMemoryError&#xff08;\u5806\u56fa\u5b9a 20MB&#xff0c;\u6ea2\u51fa\u65f6\u751f\u6210\u5185\u5b58\u5feb\u7167&#xff09;\u3002<\/li>\n<li>\u6d4b\u8bd5\u4ee3\u7801&#xff1a; public class HeapOOMTest {<br \/>\n    static class OOMObject {}<br \/>\n    public static void main(String[] args) {<br \/>\n        List&lt;OOMObject&gt; list &#061; new ArrayList&lt;&gt;();<br \/>\n        while (true) {<br \/>\n            list.add(new OOMObject()); \/\/ \u65e0\u9650\u521b\u5efa\u5bf9\u8c61&#xff0c;\u65e0\u6cd5\u56de\u6536<br \/>\n        }<br \/>\n    }<br \/>\n}\n <\/li>\n<li>\u6392\u67e5\u601d\u8def&#xff1a;\u901a\u8fc7 MAT \u7b49\u5de5\u5177\u5206\u6790\u5185\u5b58\u5feb\u7167&#xff0c;\u5224\u65ad\u662f \u201c\u5185\u5b58\u6cc4\u6f0f\u201d&#xff08;\u5bf9\u8c61\u65e0\u7528\u4f46\u65e0\u6cd5\u56de\u6536&#xff09;\u8fd8\u662f \u201c\u5185\u5b58\u6ea2\u51fa\u201d&#xff08;\u5bf9\u8c61\u786e\u5b9e\u9700\u8981\u5b58\u6d3b&#xff0c;\u4f46\u5806\u5185\u5b58\u4e0d\u8db3&#xff09;&#xff1b;\u524d\u8005\u4fee\u590d\u4ee3\u7801\u91ca\u653e\u5f15\u7528&#xff0c;\u540e\u8005\u589e\u5927-Xmx\u53c2\u6570\u3002<\/li>\n<\/ul>\n<h5 id=\"%EF%BC%882%EF%BC%89%E8%99%9A%E6%8B%9F%E6%9C%BA%E6%A0%88%20%2F%20%E6%9C%AC%E5%9C%B0%E6%96%B9%E6%B3%95%E6%A0%88%E6%BA%A2%E5%87%BA\">&#xff08;2&#xff09;\u865a\u62df\u673a\u6808 \/ \u672c\u5730\u65b9\u6cd5\u6808\u6ea2\u51fa<\/h5>\n<p>HotSpot \u5c06\u865a\u62df\u673a\u6808\u548c\u672c\u5730\u65b9\u6cd5\u6808\u5408\u4e8c\u4e3a\u4e00&#xff0c;\u6ea2\u51fa\u5206\u4e3a\u4e24\u79cd\u60c5\u51b5&#xff1a;<\/p>\n<ul>\n<li>StackOverflowError&#xff1a;\u7ebf\u7a0b\u8bf7\u6c42\u7684\u6808\u6df1\u5ea6\u8d85\u8fc7\u865a\u62df\u673a\u5141\u8bb8\u7684\u6700\u5927\u6df1\u5ea6&#xff08;\u5355\u7ebf\u7a0b\u9012\u5f52\u8fc7\u6df1&#xff09;\u3002\n<ul>\n<li>\u6d4b\u8bd5\u914d\u7f6e&#xff1a;-Xss128k&#xff08;\u51cf\u5c0f\u6808\u5bb9\u91cf&#xff0c;\u6613\u89e6\u53d1\u6ea2\u51fa&#xff09;\u3002<\/li>\n<li>\u6d4b\u8bd5\u4ee3\u7801&#xff1a; public class StackOverflowTest {<br \/>\n    private int stackLength &#061; 1;<br \/>\n    public void stackLeak() {<br \/>\n        stackLength&#043;&#043;;<br \/>\n        stackLeak(); \/\/ \u65e0\u9650\u9012\u5f52<br \/>\n    }<br \/>\n    public static void main(String[] args) {<br \/>\n        StackOverflowTest test &#061; new StackOverflowTest();<br \/>\n        try {<br \/>\n            test.stackLeak();<br \/>\n        } catch (Throwable e) {<br \/>\n            System.out.println(&#034;\u6808\u6df1\u5ea6&#xff1a;&#034; &#043; test.stackLength);<br \/>\n            throw e;<br \/>\n        }<br \/>\n    }<br \/>\n}\n <\/li>\n<\/ul>\n<\/li>\n<li>OutOfMemoryError&#xff1a;\u865a\u62df\u673a\u6269\u5c55\u6808\u65f6\u65e0\u6cd5\u7533\u8bf7\u5230\u8db3\u591f\u5185\u5b58&#xff08;\u591a\u7ebf\u7a0b\u521b\u5efa\u8fc7\u591a&#xff0c;\u8017\u5c3d\u7cfb\u7edf\u5185\u5b58&#xff09;\u3002\n<ul>\n<li>\u6d4b\u8bd5\u4ee3\u7801&#xff1a; public class StackOOMTest {<br \/>\n    public void dontStop() {<br \/>\n        while (true) {}<br \/>\n    }<br \/>\n    public void stackLeakByThread() {<br \/>\n        while (true) {<br \/>\n            new Thread(() -&gt; dontStop()).start(); \/\/ \u65e0\u9650\u521b\u5efa\u7ebf\u7a0b<br \/>\n        }<br \/>\n    }<br \/>\n    public static void main(String[] args) {<br \/>\n        new StackOOMTest().stackLeakByThread();<br \/>\n    }<br \/>\n}\n <\/li>\n<li>\u6ce8\u610f&#xff1a;\u8be5\u4ee3\u7801\u4f1a\u8017\u5c3d\u7cfb\u7edf\u5185\u5b58&#xff0c;\u8fd0\u884c\u524d\u9700\u4fdd\u5b58\u5de5\u4f5c\u3002<\/li>\n<\/ul>\n<\/li>\n<li>\u6392\u67e5\u601d\u8def&#xff1a;StackOverflowError \u9700\u51cf\u5c11\u9012\u5f52\u6df1\u5ea6\u6216\u589e\u5927-Xss&#xff1b;OutOfMemoryError \u9700\u51cf\u5c11\u7ebf\u7a0b\u6570&#xff0c;\u6216\u901a\u8fc7\u51cf\u5c0f\u5806\u5185\u5b58\u3001\u6808\u5bb9\u91cf\u6362\u53d6\u66f4\u591a\u7ebf\u7a0b\u521b\u5efa\u7a7a\u95f4\u3002<\/li>\n<\/ul>\n<h5 id=\"%EF%BC%883%EF%BC%89%E5%85%83%E7%A9%BA%E9%97%B4%E6%BA%A2%E5%87%BA%EF%BC%88java.lang.OutOfMemoryError%3A%20Metaspace%EF%BC%89\">&#xff08;3&#xff09;\u5143\u7a7a\u95f4\u6ea2\u51fa&#xff08;java.lang.OutOfMemoryError: Metaspace&#xff09;<\/h5>\n<ul>\n<li>\u89e6\u53d1\u6761\u4ef6&#xff1a;\u52a0\u8f7d\u8fc7\u591a\u7c7b&#xff08;\u5982\u52a8\u6001\u751f\u6210\u7c7b\u3001\u4f9d\u8d56\u8fc7\u591a jar \u5305&#xff09;&#xff0c;\u5143\u7a7a\u95f4&#xff08;\u672c\u5730\u5185\u5b58&#xff09;\u4e0d\u8db3\u3002<\/li>\n<li>\u6d4b\u8bd5\u914d\u7f6e&#xff1a;-XX:MaxMetaspaceSize&#061;10m&#xff08;\u9650\u5236\u5143\u7a7a\u95f4\u6700\u5927 10MB&#xff09;\u3002<\/li>\n<li>\u6392\u67e5\u601d\u8def&#xff1a;\u589e\u5927-XX:MaxMetaspaceSize\u53c2\u6570&#xff0c;\u6216\u51cf\u5c11\u4e0d\u5fc5\u8981\u7684\u7c7b\u52a0\u8f7d&#xff08;\u5982\u6e05\u7406\u5197\u4f59\u4f9d\u8d56\u3001\u907f\u514d\u52a8\u6001\u7c7b\u6ee5\u7528&#xff09;\u3002<\/li>\n<\/ul>\n<h3 id=\"%E4%BA%94%E3%80%81%E7%B1%BB%E5%8A%A0%E8%BD%BD%E6%9C%BA%E5%88%B6\">\u4e94\u3001\u7c7b\u52a0\u8f7d\u673a\u5236<\/h3>\n<p>\u7c7b\u52a0\u8f7d\u662f JVM \u5c06\u5b57\u8282\u7801\u6587\u4ef6\u8f6c\u6362\u4e3a\u53ef\u6267\u884c\u4ee3\u7801\u7684\u8fc7\u7a0b&#xff0c;\u6838\u5fc3\u5305\u62ec \u201c\u7c7b\u52a0\u8f7d\u6d41\u7a0b\u201d\u201c\u53cc\u4eb2\u59d4\u6d3e\u6a21\u578b\u201d\u201c\u7834\u574f\u53cc\u4eb2\u59d4\u6d3e\u6a21\u578b\u7684\u573a\u666f\u201d \u4e09\u90e8\u5206\u3002<\/p>\n<h4 id=\"1.%20%E7%B1%BB%E7%9A%84%E7%94%9F%E5%91%BD%E5%91%A8%E6%9C%9F\">1. \u7c7b\u7684\u751f\u547d\u5468\u671f<\/h4>\n<p>\u4e00\u4e2a\u7c7b\u4ece\u52a0\u8f7d\u5230\u5378\u8f7d\u7684\u5b8c\u6574\u751f\u547d\u5468\u671f\u4e3a&#xff1a;\u52a0\u8f7d \u2192 \u8fde\u63a5&#xff08;\u9a8c\u8bc1\u2192\u51c6\u5907\u2192\u89e3\u6790&#xff09; \u2192 \u521d\u59cb\u5316 \u2192 \u4f7f\u7528 \u2192 \u5378\u8f7d\u3002\u5176\u4e2d \u201c\u52a0\u8f7d\u3001\u9a8c\u8bc1\u3001\u51c6\u5907\u3001\u89e3\u6790\u3001\u521d\u59cb\u5316\u201d \u662f\u7c7b\u52a0\u8f7d\u7684\u6838\u5fc3\u6d41\u7a0b&#xff0c;\u987a\u5e8f\u56fa\u5b9a\u3002<\/p>\n<h4 id=\"2.%20%E7%B1%BB%E5%8A%A0%E8%BD%BD%E6%A0%B8%E5%BF%83%E6%B5%81%E7%A8%8B\">2. \u7c7b\u52a0\u8f7d\u6838\u5fc3\u6d41\u7a0b<\/h4>\n<h5 id=\"%EF%BC%881%EF%BC%89%E5%8A%A0%E8%BD%BD%EF%BC%88Loading%EF%BC%89\">&#xff08;1&#xff09;\u52a0\u8f7d&#xff08;Loading&#xff09;<\/h5>\n<ul>\n<li>\u6838\u5fc3\u4efb\u52a1&#xff1a;\n<li>\u901a\u8fc7\u7c7b\u7684\u5168\u9650\u5b9a\u540d&#xff08;\u5982java.lang.String&#xff09;\u83b7\u53d6\u5b9a\u4e49\u8be5\u7c7b\u7684\u4e8c\u8fdb\u5236\u5b57\u8282\u6d41&#xff08;\u53ef\u4ece.class \u6587\u4ef6\u3001\u7f51\u7edc\u3001\u5185\u5b58\u7b49\u6765\u6e90\u83b7\u53d6&#xff09;\u3002<\/li>\n<li>\u5c06\u5b57\u8282\u6d41\u7684\u9759\u6001\u5b58\u50a8\u7ed3\u6784\u8f6c\u6362\u4e3a\u65b9\u6cd5\u533a\u7684\u8fd0\u884c\u65f6\u6570\u636e\u7ed3\u6784&#xff08;\u7c7b\u5143\u4fe1\u606f&#xff09;\u3002<\/li>\n<li>\u5728\u5185\u5b58\u4e2d\u751f\u6210\u4e00\u4e2a\u4ee3\u8868\u8be5\u7c7b\u7684 java.lang.Class \u5bf9\u8c61&#xff0c;\u4f5c\u4e3a\u65b9\u6cd5\u533a\u4e2d\u8be5\u7c7b\u6570\u636e\u7684\u8bbf\u95ee\u5165\u53e3&#xff08;\u5b58\u50a8\u5728\u5806\u4e2d&#xff09;\u3002<\/li>\n<\/li>\n<li>\u5173\u952e\u8bf4\u660e&#xff1a;\u201c\u52a0\u8f7d\u201d \u662f \u201c\u7c7b\u52a0\u8f7d&#xff08;Class Loading&#xff09;\u201d \u7684\u7b2c\u4e00\u6b65&#xff0c;\u4e8c\u8005\u4e0d\u53ef\u6df7\u6dc6 \u2014\u2014\u201c\u7c7b\u52a0\u8f7d\u201d \u662f\u5b8c\u6574\u6d41\u7a0b&#xff08;\u52a0\u8f7d\u2192\u8fde\u63a5\u2192\u521d\u59cb\u5316&#xff09;&#xff0c;\u201c\u52a0\u8f7d\u201d \u4ec5\u6307\u4e0a\u8ff0\u4e09\u6b65\u64cd\u4f5c\u3002<\/li>\n<\/ul>\n<h5 id=\"%EF%BC%882%EF%BC%89%E9%AA%8C%E8%AF%81%EF%BC%88Verification%EF%BC%89\">&#xff08;2&#xff09;\u9a8c\u8bc1&#xff08;Verification&#xff09;<\/h5>\n<ul>\n<li>\u6838\u5fc3\u76ee\u7684&#xff1a;\u786e\u4fdd\u5b57\u8282\u7801\u6587\u4ef6\u7684\u4fe1\u606f\u7b26\u5408\u300aJava \u865a\u62df\u673a\u89c4\u8303\u300b&#xff0c;\u907f\u514d\u6076\u610f\u6216\u65e0\u6548\u5b57\u8282\u7801\u5371\u5bb3 JVM \u5b89\u5168\u3002<\/li>\n<li>\u9a8c\u8bc1\u5185\u5bb9&#xff1a;\n<li>\u6587\u4ef6\u683c\u5f0f\u9a8c\u8bc1&#xff1a;\u9a8c\u8bc1\u5b57\u8282\u7801\u6587\u4ef6\u7684\u9b54\u6570\u3001\u7248\u672c\u53f7\u3001\u5e38\u91cf\u6c60\u683c\u5f0f\u7b49&#xff08;\u786e\u4fdd\u662f\u5408\u6cd5\u7684.class \u6587\u4ef6&#xff09;\u3002<\/li>\n<li>\u5b57\u8282\u7801\u9a8c\u8bc1&#xff1a;\u9a8c\u8bc1\u5b57\u8282\u7801\u6307\u4ee4\u7684\u8bed\u4e49\u5408\u6cd5\u6027&#xff08;\u5982\u907f\u514d\u975e\u6cd5\u8df3\u8f6c\u3001\u7c7b\u578b\u8f6c\u6362\u9519\u8bef&#xff09;\u3002<\/li>\n<li>\u7b26\u53f7\u5f15\u7528\u9a8c\u8bc1&#xff1a;\u9a8c\u8bc1\u5e38\u91cf\u6c60\u4e2d\u7684\u7b26\u53f7\u5f15\u7528&#xff08;\u7c7b\u3001\u5b57\u6bb5\u3001\u65b9\u6cd5\u5f15\u7528&#xff09;\u662f\u5426\u6709\u6548&#xff08;\u5982\u5f15\u7528\u7684\u7c7b\u662f\u5426\u5b58\u5728&#xff09;\u3002<\/li>\n<\/li>\n<\/ul>\n<h5 id=\"%EF%BC%883%EF%BC%89%E5%87%86%E5%A4%87%EF%BC%88Preparation%EF%BC%89\">&#xff08;3&#xff09;\u51c6\u5907&#xff08;Preparation&#xff09;<\/h5>\n<ul>\n<li>\u6838\u5fc3\u4efb\u52a1&#xff1a;\u4e3a\u7c7b\u4e2d\u9759\u6001\u53d8\u91cf&#xff08;\u88abstatic\u4fee\u9970\u7684\u53d8\u91cf&#xff09;\u5206\u914d\u5185\u5b58&#xff0c;\u5e76\u8bbe\u7f6e \u201c\u9ed8\u8ba4\u521d\u59cb\u503c\u201d&#xff08;\u800c\u975e\u4ee3\u7801\u4e2d\u6307\u5b9a\u7684\u521d\u59cb\u503c&#xff09;\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;\u82e5\u7c7b\u4e2d\u6709public static int value &#061; 123;&#xff0c;\u51c6\u5907\u9636\u6bb5\u4f1a\u4e3avalue\u5206\u914d\u5185\u5b58&#xff0c;\u8bbe\u7f6e\u9ed8\u8ba4\u503c 0&#xff08;int \u7c7b\u578b\u9ed8\u8ba4\u503c&#xff09;&#xff0c;123\u7684\u8d4b\u503c\u4f1a\u5728\u521d\u59cb\u5316\u9636\u6bb5\u6267\u884c\u3002<\/li>\n<li>\u7279\u6b8a\u60c5\u51b5&#xff1a;\u82e5\u9759\u6001\u53d8\u91cf\u88abfinal\u4fee\u9970&#xff08;public static final int value &#061; 123;&#xff09;&#xff0c;\u51c6\u5907\u9636\u6bb5\u4f1a\u76f4\u63a5\u8bbe\u7f6e\u4e3a 123\u2014\u2014final\u9759\u6001\u53d8\u91cf\u662f \u201c\u5e38\u91cf\u201d&#xff0c;\u7f16\u8bd1\u65f6\u5df2\u786e\u5b9a\u503c&#xff0c;\u5b58\u50a8\u5728\u5e38\u91cf\u6c60\u3002<\/li>\n<\/ul>\n<h5 id=\"%EF%BC%884%EF%BC%89%E8%A7%A3%E6%9E%90%EF%BC%88Resolution%EF%BC%89\">&#xff08;4&#xff09;\u89e3\u6790&#xff08;Resolution&#xff09;<\/h5>\n<ul>\n<li>\u6838\u5fc3\u4efb\u52a1&#xff1a;\u5c06\u5e38\u91cf\u6c60\u4e2d\u7684 \u201c\u7b26\u53f7\u5f15\u7528\u201d \u66ff\u6362\u4e3a \u201c\u76f4\u63a5\u5f15\u7528\u201d\u3002<\/li>\n<li>\u6982\u5ff5\u533a\u5206&#xff1a;\n<ul>\n<li>\u7b26\u53f7\u5f15\u7528&#xff1a;\u7528\u5b57\u7b26\u4e32\u63cf\u8ff0\u76ee\u6807&#xff08;\u5982Ljava\/lang\/String;\u8868\u793a String \u7c7b&#xff09;&#xff0c;\u4e0e\u5185\u5b58\u5730\u5740\u65e0\u5173\u3002<\/li>\n<li>\u76f4\u63a5\u5f15\u7528&#xff1a;\u6307\u5411\u76ee\u6807\u7684\u5185\u5b58\u5730\u5740&#xff08;\u5982\u5bf9\u8c61\u6307\u9488\u3001\u65b9\u6cd5\u5165\u53e3\u5730\u5740&#xff09;&#xff0c;\u53ef\u76f4\u63a5\u8bbf\u95ee\u76ee\u6807\u3002<\/li>\n<\/ul>\n<\/li>\n<li>\u89e3\u6790\u5bf9\u8c61&#xff1a;\u7c7b\u3001\u63a5\u53e3\u3001\u5b57\u6bb5\u3001\u65b9\u6cd5\u3001\u65b9\u6cd5\u7c7b\u578b\u7b49\u3002<\/li>\n<\/ul>\n<h5 id=\"%EF%BC%885%EF%BC%89%E5%88%9D%E5%A7%8B%E5%8C%96%EF%BC%88Initialization%EF%BC%89\">&#xff08;5&#xff09;\u521d\u59cb\u5316&#xff08;Initialization&#xff09;<\/h5>\n<ul>\n<li>\u6838\u5fc3\u4efb\u52a1&#xff1a;\u6267\u884c\u7c7b\u6784\u9020\u5668&lt;clinit&gt;()\u65b9\u6cd5&#xff0c;\u5b8c\u6210\u9759\u6001\u53d8\u91cf\u7684\u8d4b\u503c&#xff08;\u4ee3\u7801\u4e2d\u6307\u5b9a\u7684\u521d\u59cb\u503c&#xff09;\u548c\u9759\u6001\u4ee3\u7801\u5757\u7684\u6267\u884c\u3002<\/li>\n<li>\u5173\u952e\u7ec6\u8282&#xff1a;\n<li>&lt;clinit&gt;()\u65b9\u6cd5\u7531\u7f16\u8bd1\u5668\u81ea\u52a8\u751f\u6210&#xff0c;\u6574\u5408\u4e86\u9759\u6001\u53d8\u91cf\u8d4b\u503c\u8bed\u53e5\u548c\u9759\u6001\u4ee3\u7801\u5757&#xff08;\u6309\u4ee3\u7801\u987a\u5e8f\u6267\u884c&#xff09;\u3002<\/li>\n<li>\u82e5\u7c7b\u4e2d\u65e0\u9759\u6001\u53d8\u91cf\u548c\u9759\u6001\u4ee3\u7801\u5757&#xff0c;\u7f16\u8bd1\u5668\u4e0d\u4f1a\u751f\u6210&lt;clinit&gt;()\u65b9\u6cd5\u3002<\/li>\n<li>\u7236\u7c7b\u7684&lt;clinit&gt;()\u65b9\u6cd5\u4f1a\u5148\u4e8e\u5b50\u7c7b\u6267\u884c&#xff08;\u4fdd\u8bc1\u7236\u7c7b\u9759\u6001\u53d8\u91cf\u521d\u59cb\u5316\u5b8c\u6210&#xff09;\u3002<\/li>\n<li>\u521d\u59cb\u5316\u9636\u6bb5\u662f\u7c7b\u52a0\u8f7d\u6d41\u7a0b\u4e2d\u552f\u4e00\u7531\u5e94\u7528\u7a0b\u5e8f\u4e3b\u5bfc\u7684\u9636\u6bb5&#xff0c;\u4ec5\u5728\u7c7b\u88ab\u9996\u6b21\u4e3b\u52a8\u4f7f\u7528\u65f6\u89e6\u53d1&#xff08;\u5982\u521b\u5efa\u5bf9\u8c61\u3001\u8c03\u7528\u9759\u6001\u65b9\u6cd5\u3001\u8bbf\u95ee\u9759\u6001\u53d8\u91cf&#xff09;\u3002<\/li>\n<\/li>\n<\/ul>\n<h4 id=\"3.%20%E5%8F%8C%E4%BA%B2%E5%A7%94%E6%B4%BE%E6%A8%A1%E5%9E%8B\">3. \u53cc\u4eb2\u59d4\u6d3e\u6a21\u578b<\/h4>\n<h5 id=\"%EF%BC%881%EF%BC%89%E7%B1%BB%E5%8A%A0%E8%BD%BD%E5%99%A8%E5%B1%82%E6%AC%A1%E7%BB%93%E6%9E%84\">&#xff08;1&#xff09;\u7c7b\u52a0\u8f7d\u5668\u5c42\u6b21\u7ed3\u6784<\/h5>\n<p>JVM \u4e2d\u5b58\u5728\u591a\u5c42\u7c7b\u52a0\u8f7d\u5668&#xff0c;\u81ea JDK1.2 \u4ee5\u6765\u5f62\u6210\u56fa\u5b9a\u67b6\u6784&#xff1a;<\/p>\n<ul>\n<li>\u542f\u52a8\u7c7b\u52a0\u8f7d\u5668&#xff08;Bootstrap ClassLoader&#xff09;&#xff1a;\u6700\u9876\u5c42&#xff0c;\u7531 C&#043;&#043; \u5b9e\u73b0&#xff0c;\u662f JVM \u7684\u4e00\u90e8\u5206&#xff1b;\u52a0\u8f7d JDK \u6838\u5fc3\u7c7b\u5e93&#xff08;$JAVA_HOME\/lib\u76ee\u5f55\u4e0b\u7684 jar \u5305&#xff0c;\u5982 rt.jar&#xff09;\u3002<\/li>\n<li>\u6269\u5c55\u7c7b\u52a0\u8f7d\u5668&#xff08;Extension ClassLoader&#xff09;&#xff1a;\u7531 Java \u5b9e\u73b0&#xff0c;\u52a0\u8f7d$JAVA_HOME\/lib\/ext\u76ee\u5f55\u4e0b\u7684\u6269\u5c55\u7c7b\u5e93\u3002<\/li>\n<li>\u5e94\u7528\u7a0b\u5e8f\u7c7b\u52a0\u8f7d\u5668&#xff08;Application ClassLoader&#xff09;&#xff1a;\u7531 Java \u5b9e\u73b0&#xff0c;\u4e5f\u79f0\u7cfb\u7edf\u7c7b\u52a0\u8f7d\u5668&#xff1b;\u52a0\u8f7d CLASSPATH \u6307\u5b9a\u7684\u7c7b&#xff08;\u5e94\u7528\u7a0b\u5e8f\u4ee3\u7801\u3001\u7b2c\u4e09\u65b9 jar \u5305&#xff09;\u3002<\/li>\n<li>\u81ea\u5b9a\u4e49\u7c7b\u52a0\u8f7d\u5668&#xff1a;\u7ee7\u627fjava.lang.ClassLoader&#xff0c;\u7531\u5f00\u53d1\u8005\u5b9e\u73b0&#xff0c;\u7528\u4e8e\u52a0\u8f7d\u7279\u6b8a\u6765\u6e90\u7684\u7c7b&#xff08;\u5982\u52a0\u5bc6\u5b57\u8282\u7801\u3001\u7f51\u7edc\u5b57\u8282\u7801&#xff09;\u3002<\/li>\n<\/ul>\n<h5 id=\"%EF%BC%882%EF%BC%89%E5%8F%8C%E4%BA%B2%E5%A7%94%E6%B4%BE%E6%A8%A1%E5%9E%8B%E7%9A%84%E5%B7%A5%E4%BD%9C%E6%B5%81%E7%A8%8B\">&#xff08;2&#xff09;\u53cc\u4eb2\u59d4\u6d3e\u6a21\u578b\u7684\u5de5\u4f5c\u6d41\u7a0b<\/h5>\n<p>\u201c\u53cc\u4eb2\u59d4\u6d3e\u201d \u662f\u7c7b\u52a0\u8f7d\u7684\u6838\u5fc3\u89c4\u5219&#xff1a;\u5f53\u4e00\u4e2a\u7c7b\u52a0\u8f7d\u5668\u6536\u5230\u7c7b\u52a0\u8f7d\u8bf7\u6c42\u65f6&#xff0c;\u4e0d\u4f1a\u76f4\u63a5\u52a0\u8f7d&#xff0c;\u800c\u662f\u5148\u5c06\u8bf7\u6c42\u59d4\u6d3e\u7ed9\u7236\u7c7b\u52a0\u8f7d\u5668&#xff1b;\u7236\u7c7b\u52a0\u8f7d\u5668\u82e5\u65e0\u6cd5\u52a0\u8f7d&#xff08;\u641c\u7d22\u8303\u56f4\u4e2d\u65e0\u8be5\u7c7b&#xff09;&#xff0c;\u5b50\u7c7b\u52a0\u8f7d\u5668\u624d\u4f1a\u5c1d\u8bd5\u81ea\u5df1\u52a0\u8f7d\u3002\u6d41\u7a0b\u5982\u4e0b&#xff1a;<\/p>\n<li>\u5e94\u7528\u7a0b\u5e8f\u7c7b\u52a0\u8f7d\u5668\u6536\u5230\u52a0\u8f7d\u8bf7\u6c42&#xff0c;\u5148\u59d4\u6d3e\u7ed9\u6269\u5c55\u7c7b\u52a0\u8f7d\u5668\u3002<\/li>\n<li>\u6269\u5c55\u7c7b\u52a0\u8f7d\u5668\u6536\u5230\u8bf7\u6c42&#xff0c;\u59d4\u6d3e\u7ed9\u542f\u52a8\u7c7b\u52a0\u8f7d\u5668\u3002<\/li>\n<li>\u542f\u52a8\u7c7b\u52a0\u8f7d\u5668\u5728\u6838\u5fc3\u7c7b\u5e93\u4e2d\u641c\u7d22&#xff0c;\u82e5\u627e\u5230\u5219\u52a0\u8f7d&#xff1b;\u82e5\u672a\u627e\u5230&#xff0c;\u8fd4\u56de\u7ed9\u6269\u5c55\u7c7b\u52a0\u8f7d\u5668\u3002<\/li>\n<li>\u6269\u5c55\u7c7b\u52a0\u8f7d\u5668\u5728\u6269\u5c55\u7c7b\u5e93\u4e2d\u641c\u7d22&#xff0c;\u82e5\u627e\u5230\u5219\u52a0\u8f7d&#xff1b;\u82e5\u672a\u627e\u5230&#xff0c;\u8fd4\u56de\u7ed9\u5e94\u7528\u7a0b\u5e8f\u7c7b\u52a0\u8f7d\u5668\u3002<\/li>\n<li>\u5e94\u7528\u7a0b\u5e8f\u7c7b\u52a0\u8f7d\u5668\u5728 CLASSPATH \u4e2d\u641c\u7d22&#xff0c;\u82e5\u627e\u5230\u5219\u52a0\u8f7d&#xff1b;\u82e5\u672a\u627e\u5230&#xff0c;\u629b\u51faClassNotFoundException\u3002<\/li>\n<h5 id=\"%EF%BC%883%EF%BC%89%E5%8F%8C%E4%BA%B2%E5%A7%94%E6%B4%BE%E6%A8%A1%E5%9E%8B%E7%9A%84%E6%A0%B8%E5%BF%83%E4%BC%98%E5%8A%BF\">&#xff08;3&#xff09;\u53cc\u4eb2\u59d4\u6d3e\u6a21\u578b\u7684\u6838\u5fc3\u4f18\u52bf<\/h5>\n<li>\u907f\u514d\u7c7b\u91cd\u590d\u52a0\u8f7d&#xff1a;\u82e5\u7236\u7c7b\u52a0\u8f7d\u5668\u5df2\u52a0\u8f7d\u67d0\u7c7b&#xff0c;\u5b50\u7c7b\u52a0\u8f7d\u5668\u65e0\u9700\u91cd\u590d\u52a0\u8f7d&#xff0c;\u8282\u7701\u5185\u5b58\u3002<\/li>\n<li>\u4fdd\u8bc1\u6838\u5fc3\u7c7b\u5e93\u5b89\u5168&#xff1a;\u6838\u5fc3\u7c7b\u5e93&#xff08;\u5982java.lang.Object&#xff09;\u7531\u542f\u52a8\u7c7b\u52a0\u8f7d\u5668\u52a0\u8f7d&#xff0c;\u5f00\u53d1\u8005\u65e0\u6cd5\u901a\u8fc7\u81ea\u5b9a\u4e49\u7c7b\u52a0\u8f7d\u5668\u66ff\u6362\u6838\u5fc3\u7c7b&#xff08;\u5982\u81ea\u5b9a\u4e49java.lang.Object\u7c7b&#xff09;&#xff0c;\u907f\u514d\u6076\u610f\u4ee3\u7801\u7be1\u6539\u6838\u5fc3\u529f\u80fd\u3002<\/li>\n<h4 id=\"4.%20%E7%A0%B4%E5%9D%8F%E5%8F%8C%E4%BA%B2%E5%A7%94%E6%B4%BE%E6%A8%A1%E5%9E%8B%E7%9A%84%E6%A1%88%E4%BE%8B%EF%BC%88SPI%20%E6%9C%BA%E5%88%B6%EF%BC%9AJDBC%EF%BC%89\">4. \u7834\u574f\u53cc\u4eb2\u59d4\u6d3e\u6a21\u578b\u7684\u6848\u4f8b&#xff08;SPI \u673a\u5236&#xff1a;JDBC&#xff09;<\/h4>\n<p>\u53cc\u4eb2\u59d4\u6d3e\u6a21\u578b\u867d\u6709\u4f18\u52bf&#xff0c;\u4f46\u5728\u67d0\u4e9b\u573a\u666f\u4e0b\u9700 \u201c\u7834\u574f\u201d \u4ee5\u6ee1\u8db3\u529f\u80fd\u9700\u6c42&#xff0c;\u6700\u5178\u578b\u7684\u6848\u4f8b\u662f Java \u7684 SPI&#xff08;Service Provider Interface&#xff09;\u673a\u5236&#xff0c;\u4ee5 JDBC \u4e3a\u4f8b&#xff1a;<\/p>\n<h5 id=\"%EF%BC%881%EF%BC%89%E9%97%AE%E9%A2%98%E8%83%8C%E6%99%AF\">&#xff08;1&#xff09;\u95ee\u9898\u80cc\u666f<\/h5>\n<ul>\n<li>JDBC \u7684\u6838\u5fc3\u63a5\u53e3&#xff08;java.sql.Driver\u3001DriverManager&#xff09;\u5b9a\u4e49\u5728 JDK \u7684 rt.jar \u5305\u4e2d&#xff0c;\u7531\u542f\u52a8\u7c7b\u52a0\u8f7d\u5668\u52a0\u8f7d\u3002<\/li>\n<li>\u6570\u636e\u5e93\u9a71\u52a8&#xff08;\u5982 MySQL \u7684com.mysql.cj.jdbc.Driver&#xff09;\u662f\u7b2c\u4e09\u65b9\u5b9e\u73b0&#xff0c;\u5b58\u5728\u4e8e CLASSPATH \u4e2d\u7684 mysql-connector-java.jar \u5305&#xff0c;\u9700\u7531\u5e94\u7528\u7a0b\u5e8f\u7c7b\u52a0\u8f7d\u5668\u52a0\u8f7d\u3002<\/li>\n<li>\u6309\u53cc\u4eb2\u59d4\u6d3e\u6a21\u578b&#xff0c;\u542f\u52a8\u7c7b\u52a0\u8f7d\u5668\u52a0\u8f7d\u7684DriverManager\u65e0\u6cd5\u8bbf\u95ee\u5e94\u7528\u7a0b\u5e8f\u7c7b\u52a0\u8f7d\u5668\u52a0\u8f7d\u7684\u7b2c\u4e09\u65b9\u9a71\u52a8&#xff08;\u7236\u7c7b\u52a0\u8f7d\u5668\u65e0\u6cd5\u8bbf\u95ee\u5b50\u7c7b\u52a0\u8f7d\u5668\u52a0\u8f7d\u7684\u7c7b&#xff09;&#xff0c;\u5bfc\u81f4\u9a71\u52a8\u65e0\u6cd5\u88ab\u8c03\u7528\u3002<\/li>\n<\/ul>\n<h5 id=\"%EF%BC%882%EF%BC%89%E8%A7%A3%E5%86%B3%E6%96%B9%E6%A1%88%EF%BC%9A%E7%BA%BF%E7%A8%8B%E4%B8%8A%E4%B8%8B%E6%96%87%E7%B1%BB%E5%8A%A0%E8%BD%BD%E5%99%A8\">&#xff08;2&#xff09;\u89e3\u51b3\u65b9\u6848&#xff1a;\u7ebf\u7a0b\u4e0a\u4e0b\u6587\u7c7b\u52a0\u8f7d\u5668<\/h5>\n<p>DriverManager\u901a\u8fc7 \u201c\u7ebf\u7a0b\u4e0a\u4e0b\u6587\u7c7b\u52a0\u8f7d\u5668\u201d&#xff08;Thread.currentThread ().getContextClassLoader ()&#xff09;\u7834\u574f\u53cc\u4eb2\u59d4\u6d3e\u6a21\u578b&#xff0c;\u6838\u5fc3\u6d41\u7a0b\u5982\u4e0b&#xff1a;<\/p>\n<li>\u7ebf\u7a0b\u542f\u52a8\u65f6&#xff0c;\u7ebf\u7a0b\u4e0a\u4e0b\u6587\u7c7b\u52a0\u8f7d\u5668\u9ed8\u8ba4\u8bbe\u7f6e\u4e3a\u5e94\u7528\u7a0b\u5e8f\u7c7b\u52a0\u8f7d\u5668\u3002<\/li>\n<li>DriverManager\u7684getConnection()\u65b9\u6cd5\u4e2d&#xff0c;\u901a\u8fc7\u7ebf\u7a0b\u4e0a\u4e0b\u6587\u7c7b\u52a0\u8f7d\u5668\u83b7\u53d6\u5e94\u7528\u7a0b\u5e8f\u7c7b\u52a0\u8f7d\u5668\u3002<\/li>\n<li>\u7528\u8be5\u7c7b\u52a0\u8f7d\u5668\u52a0\u8f7d\u7b2c\u4e09\u65b9\u6570\u636e\u5e93\u9a71\u52a8&#xff08;\u5982 MySQL \u7684 Driver \u7c7b&#xff09;&#xff0c;\u5b9e\u73b0\u542f\u52a8\u7c7b\u52a0\u8f7d\u5668\u52a0\u8f7d\u7684\u6838\u5fc3\u7c7b\u8bbf\u95ee\u5b50\u7c7b\u52a0\u8f7d\u5668\u52a0\u8f7d\u7684\u7b2c\u4e09\u65b9\u7c7b\u3002<\/li>\n<h5 id=\"%EF%BC%883%EF%BC%89%E6%A0%B8%E5%BF%83%E6%BA%90%E7%A0%81%EF%BC%88DriverManager%EF%BC%89\">&#xff08;3&#xff09;\u6838\u5fc3\u6e90\u7801&#xff08;DriverManager&#xff09;<\/h5>\n<p>private static Connection getConnection(String url, Properties info, Class&lt;?&gt; caller) throws SQLException {<br \/>\n    ClassLoader callerCL &#061; caller !&#061; null ? caller.getClassLoader() : null;<br \/>\n    synchronized (DriverManager.class) {<br \/>\n        if (callerCL &#061;&#061; null) {<br \/>\n            \/\/ \u83b7\u53d6\u7ebf\u7a0b\u4e0a\u4e0b\u6587\u7c7b\u52a0\u8f7d\u5668&#xff08;\u9ed8\u8ba4\u662f\u5e94\u7528\u7a0b\u5e8f\u7c7b\u52a0\u8f7d\u5668&#xff09;<br \/>\n            callerCL &#061; Thread.currentThread().getContextClassLoader();<br \/>\n        }<br \/>\n    }<br \/>\n    \/\/ \u7528callerCL\u52a0\u8f7d\u7b2c\u4e09\u65b9\u9a71\u52a8<br \/>\n    for (DriverInfo aDriver : registeredDrivers) {<br \/>\n        if (isDriverAllowed(aDriver.driver, callerCL)) {<br \/>\n            try {<br \/>\n                return aDriver.driver.connect(url, info);<br \/>\n            } catch (SQLException ex) {<br \/>\n                \/\/ \u5f02\u5e38\u5904\u7406<br \/>\n            }<br \/>\n        }<br \/>\n    }<br \/>\n    throw new SQLException(&#034;No suitable driver found&#034;);<br \/>\n}<\/p>\n<h5 id=\"%EF%BC%884%EF%BC%89%E6%80%BB%E7%BB%93\">&#xff08;4&#xff09;\u603b\u7ed3<\/h5>\n<p>\u7ebf\u7a0b\u4e0a\u4e0b\u6587\u7c7b\u52a0\u8f7d\u5668\u7684\u672c\u8d28\u662f \u201c\u9006\u5411\u59d4\u6d3e\u201d\u2014\u2014 \u5141\u8bb8\u7236\u7c7b\u52a0\u8f7d\u5668\u901a\u8fc7\u5b50\u7c7b\u52a0\u8f7d\u5668\u52a0\u8f7d\u7c7b&#xff0c;\u6253\u7834\u4e86\u53cc\u4eb2\u59d4\u6d3e\u6a21\u578b \u201c\u7236\u7c7b\u52a0\u8f7d\u5668\u4f18\u5148\u201d \u7684\u89c4\u5219&#xff0c;\u89e3\u51b3\u4e86 SPI \u673a\u5236\u4e2d\u6838\u5fc3\u7c7b\u5e93\u4e0e\u7b2c\u4e09\u65b9\u5b9e\u73b0\u7684\u534f\u4f5c\u95ee\u9898\u3002<\/p>\n<h3 id=\"%E5%85%AD%E3%80%81%E5%9E%83%E5%9C%BE%E5%9B%9E%E6%94%B6%EF%BC%88GC%EF%BC%89\">\u516d\u3001\u5783\u573e\u56de\u6536&#xff08;GC&#xff09;<\/h3>\n<p>\u5783\u573e\u56de\u6536\u662f JVM \u81ea\u52a8\u56de\u6536\u5806\u548c\u65b9\u6cd5\u533a\u4e2d\u65e0\u7528\u5bf9\u8c61\u7684\u8fc7\u7a0b&#xff0c;\u6838\u5fc3\u76ee\u6807\u662f\u91ca\u653e\u5185\u5b58&#xff0c;\u907f\u514d\u5185\u5b58\u6cc4\u6f0f\u3002GC \u7684\u6838\u5fc3\u6d41\u7a0b\u662f \u201c\u5224\u65ad\u5bf9\u8c61\u662f\u5426\u5b58\u6d3b \u2192 \u56de\u6536\u65e0\u7528\u5bf9\u8c61\u201d&#xff0c;\u6d89\u53ca \u201c\u5bf9\u8c61\u5b58\u6d3b\u5224\u65ad\u7b97\u6cd5\u201d\u201c\u5783\u573e\u56de\u6536\u7b97\u6cd5\u201d\u201c\u5783\u573e\u6536\u96c6\u5668\u201d \u4e09\u90e8\u5206\u3002<\/p>\n<h4 id=\"1.%20%E5%AF%B9%E8%B1%A1%E5%AD%98%E6%B4%BB%E5%88%A4%E6%96%AD%E7%AE%97%E6%B3%95\">1. \u5bf9\u8c61\u5b58\u6d3b\u5224\u65ad\u7b97\u6cd5<\/h4>\n<p>GC \u524d\u9700\u5148\u5224\u65ad\u5bf9\u8c61\u662f\u5426 \u201c\u6b7b\u4ea1\u201d&#xff08;\u65e0\u7528&#xff09;&#xff0c;\u4e3b\u6d41 JVM \u91c7\u7528 \u201c\u53ef\u8fbe\u6027\u5206\u6790\u7b97\u6cd5\u201d&#xff0c;\u8f85\u52a9\u4ee5 \u201c\u5f15\u7528\u8ba1\u6570\u6cd5\u201d&#xff08;\u5df2\u6dd8\u6c70&#xff09;\u3002<\/p>\n<h5 id=\"%EF%BC%881%EF%BC%89%E5%BC%95%E7%94%A8%E8%AE%A1%E6%95%B0%E6%B3%95%EF%BC%88%E6%B7%98%E6%B1%B0%EF%BC%89\">&#xff08;1&#xff09;\u5f15\u7528\u8ba1\u6570\u6cd5&#xff08;\u6dd8\u6c70&#xff09;<\/h5>\n<ul>\n<li>\u6838\u5fc3\u903b\u8f91&#xff1a;\u7ed9\u6bcf\u4e2a\u5bf9\u8c61\u6dfb\u52a0\u5f15\u7528\u8ba1\u6570\u5668&#xff0c;\u6709\u5f15\u7528\u65f6\u8ba1\u6570\u5668 &#043; 1&#xff0c;\u5f15\u7528\u5931\u6548\u65f6 &#8211; 1&#xff1b;\u8ba1\u6570\u5668\u4e3a 0 \u65f6&#xff0c;\u5bf9\u8c61\u6b7b\u4ea1\u3002<\/li>\n<li>\u4f18\u70b9&#xff1a;\u5b9e\u73b0\u7b80\u5355&#xff0c;\u5224\u5b9a\u6548\u7387\u9ad8\u3002<\/li>\n<li>\u7f3a\u70b9&#xff1a;\u65e0\u6cd5\u89e3\u51b3 \u201c\u5faa\u73af\u5f15\u7528\u201d \u95ee\u9898 \u2014\u2014 \u4e24\u4e2a\u5bf9\u8c61\u4e92\u76f8\u5f15\u7528&#xff0c;\u8ba1\u6570\u5668\u5747\u4e3a 1&#xff0c;\u4f46\u5b9e\u9645\u5df2\u65e0\u7528&#xff0c;\u65e0\u6cd5\u88ab\u56de\u6536\u3002<\/li>\n<li>\u793a\u4f8b&#xff08;\u5faa\u73af\u5f15\u7528&#xff09;&#xff1a; public class ReferenceCountTest {<br \/>\n    public Object instance &#061; null;<br \/>\n    private static final int _1MB &#061; 1024 * 1024;<br \/>\n    private byte[] bigSize &#061; new byte[2 * _1MB]; \/\/ \u5360\u7528\u5185\u5b58&#xff0c;\u4fbf\u4e8e\u89c2\u5bdfGC<\/p>\n<p>    public static void testGC() {<br \/>\n        ReferenceCountTest a &#061; new ReferenceCountTest();<br \/>\n        ReferenceCountTest b &#061; new ReferenceCountTest();<br \/>\n        a.instance &#061; b; \/\/ a\u5f15\u7528b<br \/>\n        b.instance &#061; a; \/\/ b\u5f15\u7528a<br \/>\n        a &#061; null; \/\/ \u53d6\u6d88\u5f15\u7528<br \/>\n        b &#061; null; \/\/ \u53d6\u6d88\u5f15\u7528<br \/>\n        System.gc(); \/\/ \u89e6\u53d1GC<br \/>\n    }<\/p>\n<p>    public static void main(String[] args) {<br \/>\n        testGC();<br \/>\n    }<br \/>\n}\n <\/li>\n<li>\u8fd0\u884c\u7ed3\u679c&#xff1a;GC \u65e5\u5fd7\u663e\u793a6092K-&gt;856K&#xff0c;\u8bf4\u660e\u5faa\u73af\u5f15\u7528\u7684\u5bf9\u8c61\u88ab\u56de\u6536&#xff0c;\u8bc1\u660e HotSpot \u672a\u4f7f\u7528\u5f15\u7528\u8ba1\u6570\u6cd5\u3002<\/li>\n<\/ul>\n<h5 id=\"%EF%BC%882%EF%BC%89%E5%8F%AF%E8%BE%BE%E6%80%A7%E5%88%86%E6%9E%90%E7%AE%97%E6%B3%95%EF%BC%88%E4%B8%BB%E6%B5%81%EF%BC%89\">&#xff08;2&#xff09;\u53ef\u8fbe\u6027\u5206\u6790\u7b97\u6cd5&#xff08;\u4e3b\u6d41&#xff09;<\/h5>\n<ul>\n<li>\u6838\u5fc3\u903b\u8f91&#xff1a;\u4ee5 \u201cGC Roots\u201d \u4e3a\u8d77\u59cb\u70b9&#xff0c;\u5411\u4e0b\u641c\u7d22\u5f15\u7528\u94fe&#xff1b;\u82e5\u5bf9\u8c61\u5230 GC Roots \u65e0\u4efb\u4f55\u5f15\u7528\u94fe\u76f8\u8fde&#xff08;\u4e0d\u53ef\u8fbe&#xff09;&#xff0c;\u5219\u5224\u5b9a\u4e3a\u6b7b\u4ea1\u5bf9\u8c61\u3002<\/li>\n<li>GC Roots \u7684\u53ef\u9009\u5bf9\u8c61&#xff08;Java \u8bed\u8a00\u4e2d&#xff09;&#xff1a;\n<li>\u865a\u62df\u673a\u6808&#xff08;\u6808\u5e27\u672c\u5730\u53d8\u91cf\u8868&#xff09;\u4e2d\u5f15\u7528\u7684\u5bf9\u8c61&#xff08;\u5982\u65b9\u6cd5\u53c2\u6570\u3001\u5c40\u90e8\u53d8\u91cf&#xff09;\u3002<\/li>\n<li>\u65b9\u6cd5\u533a\u4e2d\u7c7b\u9759\u6001\u5c5e\u6027\u5f15\u7528\u7684\u5bf9\u8c61&#xff08;\u5982static Object obj &#061; new Object()&#xff09;\u3002<\/li>\n<li>\u65b9\u6cd5\u533a\u4e2d\u5e38\u91cf\u5f15\u7528\u7684\u5bf9\u8c61&#xff08;\u5982final Object obj &#061; new Object()&#xff09;\u3002<\/li>\n<li>\u672c\u5730\u65b9\u6cd5\u6808\u4e2d JNI&#xff08;Native \u65b9\u6cd5&#xff09;\u5f15\u7528\u7684\u5bf9\u8c61\u3002<\/li>\n<\/li>\n<li>\u793a\u4f8b&#xff1a;\u5bf9\u8c61 Object5-Object7 \u867d\u4e92\u76f8\u5f15\u7528&#xff0c;\u4f46\u5230 GC Roots \u4e0d\u53ef\u8fbe&#xff0c;\u88ab\u5224\u5b9a\u4e3a\u53ef\u56de\u6536\u5bf9\u8c61\u3002<\/li>\n<\/ul>\n<h5 id=\"%EF%BC%883%EF%BC%89%E5%BC%95%E7%94%A8%E7%9A%84%E6%89%A9%E5%B1%95%E5%88%86%E7%B1%BB%EF%BC%88JDK1.2%EF%BC%89\">&#xff08;3&#xff09;\u5f15\u7528\u7684\u6269\u5c55\u5206\u7c7b&#xff08;JDK1.2&#xff09;<\/h5>\n<p>JDK1.2 \u540e&#xff0c;Java \u5bf9 \u201c\u5f15\u7528\u201d \u7684\u6982\u5ff5\u8fdb\u884c\u6269\u5c55&#xff0c;\u5206\u4e3a\u56db\u7ea7&#xff08;\u5f3a\u5ea6\u9012\u51cf&#xff09;&#xff0c;\u5f71\u54cd\u5bf9\u8c61\u7684\u5b58\u6d3b\u5224\u5b9a&#xff1a;<\/p>\n<li>\u5f3a\u5f15\u7528&#xff1a;\u7a0b\u5e8f\u4e2d\u666e\u904d\u5b58\u5728\u7684\u5f15\u7528&#xff08;\u5982Object obj &#061; new Object()&#xff09;&#xff0c;\u53ea\u8981\u5f3a\u5f15\u7528\u5b58\u5728&#xff0c;GC \u6c38\u4e0d\u56de\u6536\u5bf9\u8c61\u3002<\/li>\n<li>\u8f6f\u5f15\u7528&#xff1a;\u63cf\u8ff0 \u201c\u6709\u7528\u4f46\u975e\u5fc5\u9700\u201d \u7684\u5bf9\u8c61&#xff08;SoftReference\u7c7b&#xff09;&#xff0c;\u7cfb\u7edf\u5185\u5b58\u4e0d\u8db3\u65f6&#xff08;\u5373\u5c06 OOM&#xff09;&#xff0c;\u4f1a\u56de\u6536\u8f6f\u5f15\u7528\u5173\u8054\u7684\u5bf9\u8c61\u3002<\/li>\n<li>\u5f31\u5f15\u7528&#xff1a;\u63cf\u8ff0 \u201c\u975e\u5fc5\u9700\u201d \u7684\u5bf9\u8c61&#xff08;WeakReference\u7c7b&#xff09;&#xff0c;GC \u89e6\u53d1\u65f6&#xff0c;\u65e0\u8bba\u5185\u5b58\u662f\u5426\u5145\u8db3&#xff0c;\u90fd\u4f1a\u56de\u6536\u5f31\u5f15\u7528\u5173\u8054\u7684\u5bf9\u8c61\u3002<\/li>\n<li>\u865a\u5f15\u7528&#xff1a;\u6700\u5f31\u7684\u5f15\u7528&#xff08;PhantomReference\u7c7b&#xff09;&#xff0c;\u65e0\u6cd5\u901a\u8fc7\u865a\u5f15\u7528\u83b7\u53d6\u5bf9\u8c61&#xff0c;\u4ec5\u7528\u4e8e\u5728\u5bf9\u8c61\u88ab GC \u65f6\u63a5\u6536\u7cfb\u7edf\u901a\u77e5&#xff08;\u8ddf\u8e2a\u5bf9\u8c61\u56de\u6536\u72b6\u6001&#xff09;\u3002<\/li>\n<h4 id=\"2.%20%E5%9E%83%E5%9C%BE%E5%9B%9E%E6%94%B6%E7%AE%97%E6%B3%95\">2. \u5783\u573e\u56de\u6536\u7b97\u6cd5<\/h4>\n<p>\u5783\u573e\u56de\u6536\u7b97\u6cd5\u662f GC \u7684\u6838\u5fc3\u601d\u60f3&#xff0c;\u4e0d\u540c\u7b97\u6cd5\u9002\u7528\u4e8e\u4e0d\u540c\u573a\u666f&#xff0c;\u4e3b\u6d41\u7b97\u6cd5\u5305\u62ec\u4ee5\u4e0b\u56db\u79cd&#xff1a;<\/p>\n<h5 id=\"%EF%BC%881%EF%BC%89%E6%A0%87%E8%AE%B0%20-%20%E6%B8%85%E9%99%A4%E7%AE%97%E6%B3%95%EF%BC%88%E5%9F%BA%E7%A1%80%EF%BC%89\">&#xff08;1&#xff09;\u6807\u8bb0 &#8211; \u6e05\u9664\u7b97\u6cd5&#xff08;\u57fa\u7840&#xff09;<\/h5>\n<ul>\n<li>\u6838\u5fc3\u6d41\u7a0b&#xff1a;\u5206\u4e3a \u201c\u6807\u8bb0\u201d \u548c \u201c\u6e05\u9664\u201d \u4e24\u6b65\u3002\n<li>\u6807\u8bb0&#xff1a;\u901a\u8fc7\u53ef\u8fbe\u6027\u5206\u6790&#xff0c;\u6807\u8bb0\u6240\u6709\u9700\u8981\u56de\u6536\u7684\u6b7b\u4ea1\u5bf9\u8c61\u3002<\/li>\n<li>\u6e05\u9664&#xff1a;\u904d\u5386\u5806\u5185\u5b58&#xff0c;\u56de\u6536\u6240\u6709\u88ab\u6807\u8bb0\u7684\u5bf9\u8c61&#xff0c;\u91ca\u653e\u5185\u5b58\u7a7a\u95f4\u3002<\/li>\n<\/li>\n<li>\u4f18\u70b9&#xff1a;\u5b9e\u73b0\u7b80\u5355&#xff0c;\u65e0\u9700\u79fb\u52a8\u5bf9\u8c61\u3002<\/li>\n<li>\u7f3a\u70b9&#xff1a;\n<li>\u6548\u7387\u4f4e&#xff1a;\u6807\u8bb0\u548c\u6e05\u9664\u8fc7\u7a0b\u5747\u9700\u904d\u5386\u6240\u6709\u5bf9\u8c61&#xff0c;\u8017\u65f6\u8f83\u957f\u3002<\/li>\n<li>\u5185\u5b58\u788e\u7247&#xff1a;\u56de\u6536\u540e\u4ea7\u751f\u5927\u91cf\u4e0d\u8fde\u7eed\u7684\u5185\u5b58\u788e\u7247&#xff0c;\u540e\u7eed\u5206\u914d\u5927\u5bf9\u8c61\u65f6&#xff0c;\u53ef\u80fd\u56e0\u65e0\u6cd5\u627e\u5230\u8db3\u591f\u8fde\u7eed\u5185\u5b58\u800c\u63d0\u524d\u89e6\u53d1 GC\u3002<\/li>\n<\/li>\n<\/ul>\n<h5 id=\"%EF%BC%882%EF%BC%89%E5%A4%8D%E5%88%B6%E7%AE%97%E6%B3%95%EF%BC%88%E6%96%B0%E7%94%9F%E4%BB%A3%E9%A6%96%E9%80%89%EF%BC%89\">&#xff08;2&#xff09;\u590d\u5236\u7b97\u6cd5&#xff08;\u65b0\u751f\u4ee3\u9996\u9009&#xff09;<\/h5>\n<ul>\n<li>\u6838\u5fc3\u6d41\u7a0b&#xff1a;\u5c06\u53ef\u7528\u5185\u5b58\u5212\u5206\u4e3a\u5927\u5c0f\u76f8\u7b49\u7684\u4e24\u5757&#xff08;A \u533a\u548c B \u533a&#xff09;&#xff0c;\u6bcf\u6b21\u4ec5\u4f7f\u7528\u4e00\u5757\u3002\n<li>\u6807\u8bb0&#xff1a;\u6807\u8bb0 A \u533a\u4e2d\u5b58\u6d3b\u7684\u5bf9\u8c61\u3002<\/li>\n<li>\u590d\u5236&#xff1a;\u5c06 A \u533a\u5b58\u6d3b\u5bf9\u8c61\u590d\u5236\u5230 B \u533a&#xff0c;\u6309\u987a\u5e8f\u6392\u5217&#xff08;\u65e0\u5185\u5b58\u788e\u7247&#xff09;\u3002<\/li>\n<li>\u6e05\u9664&#xff1a;\u6e05\u7a7a A \u533a&#xff0c;\u4e0b\u6b21\u4f7f\u7528 B \u533a&#xff0c;\u91cd\u590d\u4e0a\u8ff0\u6d41\u7a0b\u3002<\/li>\n<\/li>\n<li>\u4f18\u70b9&#xff1a;\u5b9e\u73b0\u7b80\u5355&#xff0c;\u8fd0\u884c\u9ad8\u6548&#xff0c;\u65e0\u5185\u5b58\u788e\u7247\u3002<\/li>\n<li>\u7f3a\u70b9&#xff1a;\u5185\u5b58\u5229\u7528\u7387\u4f4e&#xff08;\u4ec5 50%&#xff09;&#xff0c;\u4e0d\u9002\u7528\u4e8e\u5bf9\u8c61\u5b58\u6d3b\u7387\u9ad8\u7684\u573a\u666f&#xff08;\u9700\u9891\u7e41\u590d\u5236&#xff09;\u3002<\/li>\n<li>\u4f18\u5316&#xff08;HotSpot \u65b0\u751f\u4ee3\u5b9e\u73b0&#xff09;&#xff1a;\u65b0\u751f\u4ee3\u4e2d 98% \u7684\u5bf9\u8c61 \u201c\u671d\u751f\u5915\u6b7b\u201d&#xff0c;\u65e0\u9700 1:1 \u5212\u5206\u5185\u5b58&#xff0c;\u800c\u662f\u5206\u4e3a 1 \u4e2a Eden \u533a&#xff08;\u5927&#xff09;\u548c 2 \u4e2a Survivor \u533a&#xff08;\u5c0f&#xff09;&#xff0c;\u9ed8\u8ba4\u6bd4\u4f8b Eden:S0:S1&#061;8:1:1\u3002\n<li>\u521d\u59cb\u5206\u914d&#xff1a;\u5bf9\u8c61\u4f18\u5148\u5728 Eden \u533a\u521b\u5efa\u3002<\/li>\n<li>Minor GC \u89e6\u53d1&#xff1a;Eden \u533a\u6ee1\u65f6&#xff0c;\u6807\u8bb0 Eden \u548c S0 \u533a\u7684\u5b58\u6d3b\u5bf9\u8c61&#xff0c;\u590d\u5236\u5230 S1 \u533a&#xff0c;\u6e05\u7a7a Eden \u548c S0 \u533a\u3002<\/li>\n<li>Survivor \u533a\u5207\u6362&#xff1a;\u4e0b\u6b21 Minor GC \u65f6&#xff0c;\u6807\u8bb0 Eden \u548c S1 \u533a\u7684\u5b58\u6d3b\u5bf9\u8c61&#xff0c;\u590d\u5236\u5230 S0 \u533a&#xff0c;\u6e05\u7a7a Eden \u548c S1 \u533a\u3002<\/li>\n<li>\u664b\u5347\u8001\u5e74\u4ee3&#xff1a;\u5bf9\u8c61\u5728 S0 \u548c S1 \u533a\u4e4b\u95f4\u590d\u5236\u6b21\u6570\u8fbe\u5230\u9608\u503c&#xff08;\u9ed8\u8ba4 15 \u6b21&#xff09;\u540e&#xff0c;\u664b\u5347\u5230\u8001\u5e74\u4ee3&#xff1b;\u82e5 Survivor \u533a\u7a7a\u95f4\u4e0d\u8db3&#xff0c;\u76f4\u63a5\u664b\u5347\u8001\u5e74\u4ee3&#xff08;\u5206\u914d\u62c5\u4fdd&#xff09;\u3002<\/li>\n<li>\u5185\u5b58\u5229\u7528\u7387&#xff1a;\u65b0\u751f\u4ee3\u53ef\u7528\u5185\u5b58\u4e3a 90%&#xff08;8&#043;1&#xff09;&#xff0c;\u4ec5 10% \u7528\u4e8e\u5b58\u50a8\u5b58\u6d3b\u5bf9\u8c61\u3002<\/li>\n<\/li>\n<\/ul>\n<h5 id=\"%EF%BC%883%EF%BC%89%E6%A0%87%E8%AE%B0%20-%20%E6%95%B4%E7%90%86%E7%AE%97%E6%B3%95%EF%BC%88%E8%80%81%E5%B9%B4%E4%BB%A3%E9%A6%96%E9%80%89%EF%BC%89\">&#xff08;3&#xff09;\u6807\u8bb0 &#8211; \u6574\u7406\u7b97\u6cd5&#xff08;\u8001\u5e74\u4ee3\u9996\u9009&#xff09;<\/h5>\n<ul>\n<li>\u6838\u5fc3\u6d41\u7a0b&#xff1a;\u7ed3\u5408 \u201c\u6807\u8bb0 &#8211; \u6e05\u9664\u201d \u548c \u201c\u590d\u5236\u201d \u7684\u4f18\u70b9&#xff0c;\u9002\u7528\u4e8e\u5bf9\u8c61\u5b58\u6d3b\u7387\u9ad8\u7684\u8001\u5e74\u4ee3\u3002\n<li>\u6807\u8bb0&#xff1a;\u6807\u8bb0\u6240\u6709\u6b7b\u4ea1\u5bf9\u8c61\u3002<\/li>\n<li>\u6574\u7406&#xff1a;\u5c06\u6240\u6709\u5b58\u6d3b\u5bf9\u8c61\u5411\u5185\u5b58\u4e00\u7aef\u79fb\u52a8&#xff0c;\u7d27\u51d1\u6392\u5217\u3002<\/li>\n<li>\u6e05\u9664&#xff1a;\u6e05\u7a7a\u5b58\u6d3b\u5bf9\u8c61\u53e6\u4e00\u7aef\u7684\u5185\u5b58\u7a7a\u95f4\u3002<\/li>\n<\/li>\n<li>\u4f18\u70b9&#xff1a;\u65e0\u5185\u5b58\u788e\u7247&#xff0c;\u5185\u5b58\u5229\u7528\u7387\u9ad8\u3002<\/li>\n<li>\u7f3a\u70b9&#xff1a;\u6548\u7387\u4f4e\u4e8e\u590d\u5236\u7b97\u6cd5&#xff08;\u9700\u79fb\u52a8\u5bf9\u8c61&#xff0c;\u989d\u5916\u6d88\u8017 CPU \u8d44\u6e90&#xff09;\u3002<\/li>\n<\/ul>\n<h5 id=\"%EF%BC%884%EF%BC%89%E5%88%86%E4%BB%A3%E6%94%B6%E9%9B%86%E7%AE%97%E6%B3%95%EF%BC%88%E5%AE%9E%E9%99%85%E5%BA%94%E7%94%A8%EF%BC%89\">&#xff08;4&#xff09;\u5206\u4ee3\u6536\u96c6\u7b97\u6cd5&#xff08;\u5b9e\u9645\u5e94\u7528&#xff09;<\/h5>\n<ul>\n<li>\u6838\u5fc3\u601d\u60f3&#xff1a;\u6839\u636e\u5bf9\u8c61\u5b58\u6d3b\u5468\u671f\u7684\u4e0d\u540c&#xff0c;\u5c06\u5806\u5206\u4e3a\u65b0\u751f\u4ee3\u548c\u8001\u5e74\u4ee3&#xff0c;\u91c7\u7528\u4e0d\u540c\u7684\u56de\u6536\u7b97\u6cd5&#xff0c;\u517c\u987e\u6548\u7387\u548c\u5185\u5b58\u5229\u7528\u7387\u3002\n<li>\u65b0\u751f\u4ee3&#xff1a;\u5bf9\u8c61\u5b58\u6d3b\u65f6\u95f4\u77ed\u3001\u5b58\u6d3b\u7387\u4f4e&#xff0c;\u91c7\u7528\u590d\u5236\u7b97\u6cd5&#xff08;\u9ad8\u6548\u3001\u65e0\u788e\u7247&#xff09;\u3002<\/li>\n<li>\u8001\u5e74\u4ee3&#xff1a;\u5bf9\u8c61\u5b58\u6d3b\u65f6\u95f4\u957f\u3001\u5b58\u6d3b\u7387\u9ad8&#xff0c;\u91c7\u7528\u6807\u8bb0 &#8211; \u6574\u7406\u7b97\u6cd5&#xff08;\u65e0\u788e\u7247\u3001\u9ad8\u5229\u7528\u7387&#xff09;\u3002<\/li>\n<\/li>\n<li>\u8865\u5145&#xff1a;\u65b9\u6cd5\u533a\u7684\u56de\u6536&#xff08;\u5143\u7a7a\u95f4&#xff09;&#xff1a;\u56de\u6536\u5e9f\u5f03\u5e38\u91cf\u548c\u65e0\u7528\u7c7b&#xff08;\u7c7b\u7684\u6240\u6709\u5b9e\u4f8b\u5df2\u56de\u6536\u3001\u7c7b\u52a0\u8f7d\u5668\u5df2\u56de\u6536\u3001\u65e0\u5f15\u7528\u6307\u5411\u7c7b\u5bf9\u8c61&#xff09;&#xff0c;\u9891\u7387\u8f83\u4f4e\u3002<\/li>\n<\/ul>\n<h5 id=\"%E9%9D%A2%E8%AF%95%E9%A2%98%EF%BC%9AMinor%20GC%20%E4%B8%8E%20Full%20GC%20%E7%9A%84%E5%8C%BA%E5%88%AB\">\u9762\u8bd5\u9898&#xff1a;Minor GC \u4e0e Full GC \u7684\u533a\u522b<\/h5>\n<table>\n<tr>\u7ef4\u5ea6Minor GC&#xff08;\u65b0\u751f\u4ee3 GC&#xff09;Full GC&#xff08;\u8001\u5e74\u4ee3 GC\/Major GC&#xff09;<\/tr>\n<tbody>\n<tr>\n<td>\u89e6\u53d1\u533a\u57df<\/td>\n<td>\u65b0\u751f\u4ee3&#xff08;Eden\/Survivor&#xff09;<\/td>\n<td>\u8001\u5e74\u4ee3&#xff08;\u53ef\u4f34\u968f Minor GC&#xff09;<\/td>\n<\/tr>\n<tr>\n<td>\u89e6\u53d1\u6761\u4ef6<\/td>\n<td>Eden \u533a\u6ee1<\/td>\n<td>\u8001\u5e74\u4ee3\u6ee1\u3001\u5143\u7a7a\u95f4\u6ee1\u3001\u8c03\u7528 System.gc () \u7b49<\/td>\n<\/tr>\n<tr>\n<td>\u56de\u6536\u7b97\u6cd5<\/td>\n<td>\u590d\u5236\u7b97\u6cd5<\/td>\n<td>\u6807\u8bb0 &#8211; \u6574\u7406\u7b97\u6cd5&#xff08;\u6216\u6807\u8bb0 &#8211; \u6e05\u9664&#xff09;<\/td>\n<\/tr>\n<tr>\n<td>\u6267\u884c\u6548\u7387<\/td>\n<td>\u5feb&#xff08;\u5bf9\u8c61\u5b58\u6d3b\u7387\u4f4e&#xff0c;\u590d\u5236\u91cf\u5c0f&#xff09;<\/td>\n<td>\u6162&#xff08;\u5bf9\u8c61\u5b58\u6d3b\u7387\u9ad8&#xff0c;\u9700\u6574\u7406&#xff09;&#xff0c;\u7ea6\u4e3a Minor GC \u7684 10 \u500d<\/td>\n<\/tr>\n<tr>\n<td>\u5f71\u54cd\u8303\u56f4<\/td>\n<td>\u4ec5\u65b0\u751f\u4ee3\u7ebf\u7a0b&#xff0c;\u5f71\u54cd\u5c0f<\/td>\n<td>\u5168\u5806\u56de\u6536&#xff0c;\u5f71\u54cd\u5927&#xff08;STW \u65f6\u95f4\u957f&#xff09;<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h4 id=\"3.%20%E5%9E%83%E5%9C%BE%E6%94%B6%E9%9B%86%E5%99%A8%EF%BC%88HotSpot%EF%BC%89\">3. \u5783\u573e\u6536\u96c6\u5668&#xff08;HotSpot&#xff09;<\/h4>\n<p>\u5783\u573e\u6536\u96c6\u5668\u662f\u5783\u573e\u56de\u6536\u7b97\u6cd5\u7684\u5177\u4f53\u5b9e\u73b0&#xff0c;HotSpot \u865a\u62df\u673a\u63d0\u4f9b\u4e86\u591a\u6b3e\u6536\u96c6\u5668&#xff0c;\u9002\u7528\u4e8e\u4e0d\u540c\u573a\u666f&#xff08;\u541e\u5410\u91cf\u3001\u4f4e\u505c\u987f&#xff09;&#xff0c;\u6838\u5fc3\u6536\u96c6\u5668\u5982\u4e0b&#xff1a;<\/p>\n<h5 id=\"%EF%BC%881%EF%BC%89%E6%A0%B8%E5%BF%83%E6%A6%82%E5%BF%B5\">&#xff08;1&#xff09;\u6838\u5fc3\u6982\u5ff5<\/h5>\n<ul>\n<li>\u5e76\u884c&#xff08;Parallel&#xff09;&#xff1a;\u591a\u6761 GC \u7ebf\u7a0b\u540c\u65f6\u5de5\u4f5c&#xff0c;\u7528\u6237\u7ebf\u7a0b\u6682\u505c&#xff08;STW&#xff09;\u3002<\/li>\n<li>\u5e76\u53d1&#xff08;Concurrent&#xff09;&#xff1a;GC \u7ebf\u7a0b\u4e0e\u7528\u6237\u7ebf\u7a0b\u540c\u65f6\u6267\u884c&#xff08;\u4ea4\u66ff\u8fd0\u884c&#xff09;&#xff0c;\u7528\u6237\u7ebf\u7a0b\u65e0\u9700\u957f\u65f6\u95f4\u6682\u505c\u3002<\/li>\n<li>\u541e\u5410\u91cf&#xff1a;CPU \u7528\u4e8e\u8fd0\u884c\u7528\u6237\u4ee3\u7801\u7684\u65f6\u95f4 \/ CPU \u603b\u6d88\u8017\u65f6\u95f4&#xff08;\u541e\u5410\u91cf &#061; \u7528\u6237\u4ee3\u7801\u65f6\u95f4 \/ (\u7528\u6237\u4ee3\u7801\u65f6\u95f4 &#043; GC \u65f6\u95f4)&#xff09;\u3002<\/li>\n<\/ul>\n<h5 id=\"%EF%BC%882%EF%BC%89%E6%94%B6%E9%9B%86%E5%99%A8%E5%88%86%E7%B1%BB%E4%B8%8E%E7%89%B9%E6%80%A7\">&#xff08;2&#xff09;\u6536\u96c6\u5668\u5206\u7c7b\u4e0e\u7279\u6027<\/h5>\n<table>\n<tr>\u6536\u96c6\u5668\u9002\u7528\u533a\u57df\u6838\u5fc3\u7279\u6027\u56de\u6536\u7b97\u6cd5\u5e76\u53d1 \/ \u5e76\u884c\u4f18\u70b9\u7f3a\u70b9<\/tr>\n<tbody>\n<tr>\n<td>Serial<\/td>\n<td>\u65b0\u751f\u4ee3<\/td>\n<td>\u5355\u7ebf\u7a0b&#xff0c;STW<\/td>\n<td>\u590d\u5236\u7b97\u6cd5<\/td>\n<td>\u4e32\u884c<\/td>\n<td>\u5b9e\u73b0\u7b80\u5355&#xff0c;\u5355 CPU \u6548\u7387\u9ad8<\/td>\n<td>\u591a CPU \u573a\u666f\u6548\u7387\u4f4e&#xff0c;STW \u65f6\u95f4\u957f<\/td>\n<\/tr>\n<tr>\n<td>ParNew<\/td>\n<td>\u65b0\u751f\u4ee3<\/td>\n<td>\u591a\u7ebf\u7a0b&#xff08;Serial \u591a\u7ebf\u7a0b\u7248&#xff09;&#xff0c;STW<\/td>\n<td>\u590d\u5236\u7b97\u6cd5<\/td>\n<td>\u5e76\u884c<\/td>\n<td>\u652f\u6301\u4e0e CMS \u914d\u5408&#xff0c;\u591a CPU \u6548\u7387\u9ad8<\/td>\n<td>\u5355 CPU \u573a\u666f\u6709\u7ebf\u7a0b\u4ea4\u4e92\u5f00\u9500<\/td>\n<\/tr>\n<tr>\n<td>Parallel Scavenge<\/td>\n<td>\u65b0\u751f\u4ee3<\/td>\n<td>\u591a\u7ebf\u7a0b&#xff0c;\u541e\u5410\u91cf\u4f18\u5148<\/td>\n<td>\u590d\u5236\u7b97\u6cd5<\/td>\n<td>\u5e76\u884c<\/td>\n<td>\u81ea\u9002\u5e94\u8c03\u8282\u7b56\u7565&#xff0c;\u53ef\u63a7\u5236\u541e\u5410\u91cf\u548c\u505c\u987f\u65f6\u95f4<\/td>\n<td>\u4e0d\u652f\u6301\u4e0e CMS \u914d\u5408<\/td>\n<\/tr>\n<tr>\n<td>Serial Old<\/td>\n<td>\u8001\u5e74\u4ee3<\/td>\n<td>\u5355\u7ebf\u7a0b&#xff0c;STW<\/td>\n<td>\u6807\u8bb0 &#8211; \u6574\u7406<\/td>\n<td>\u4e32\u884c<\/td>\n<td>\u5b9e\u73b0\u7b80\u5355&#xff0c;Client \u6a21\u5f0f\u9ed8\u8ba4<\/td>\n<td>\u591a CPU \u573a\u666f\u6548\u7387\u4f4e<\/td>\n<\/tr>\n<tr>\n<td>Parallel Old<\/td>\n<td>\u8001\u5e74\u4ee3<\/td>\n<td>\u591a\u7ebf\u7a0b&#xff0c;\u541e\u5410\u91cf\u4f18\u5148<\/td>\n<td>\u6807\u8bb0 &#8211; \u6574\u7406<\/td>\n<td>\u5e76\u884c<\/td>\n<td>\u4e0e Parallel Scavenge \u642d\u914d&#xff0c;\u541e\u5410\u91cf\u6700\u4f18<\/td>\n<td>\u505c\u987f\u65f6\u95f4\u8f83\u957f<\/td>\n<\/tr>\n<tr>\n<td>CMS&#xff08;Concurrent Mark Sweep&#xff09;<\/td>\n<td>\u8001\u5e74\u4ee3<\/td>\n<td>\u5e76\u53d1\u6536\u96c6&#xff0c;\u4f4e\u505c\u987f<\/td>\n<td>\u6807\u8bb0 &#8211; \u6e05\u9664<\/td>\n<td>\u5e76\u53d1<\/td>\n<td>\u54cd\u5e94\u901f\u5ea6\u5feb&#xff0c;STW \u65f6\u95f4\u77ed<\/td>\n<td>\u5360\u7528 CPU \u8d44\u6e90&#xff0c;\u4ea7\u751f\u5185\u5b58\u788e\u7247&#xff0c;\u65e0\u6cd5\u5904\u7406\u6d6e\u52a8\u5783\u573e<\/td>\n<\/tr>\n<tr>\n<td>G1&#xff08;Garbage First&#xff09;<\/td>\n<td>\u5168\u533a\u57df<\/td>\n<td>\u5206\u533a\u6536\u96c6&#xff0c;\u517c\u987e\u541e\u5410\u91cf\u4e0e\u4f4e\u505c\u987f<\/td>\n<td>\u6807\u8bb0 &#8211; \u6574\u7406 &#043; \u590d\u5236<\/td>\n<td>\u5e76\u53d1 &#043; \u5e76\u884c<\/td>\n<td>\u65e0\u5185\u5b58\u788e\u7247&#xff0c;\u53ef\u9884\u6d4b\u505c\u987f\u65f6\u95f4<\/td>\n<td>\u5b9e\u73b0\u590d\u6742&#xff0c;\u5c0f\u5185\u5b58\u573a\u666f\u6548\u7387\u4f4e<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h5 id=\"%EF%BC%883%EF%BC%89%E9%87%8D%E7%82%B9%E6%94%B6%E9%9B%86%E5%99%A8%E8%AF%A6%E8%A7%A3\">&#xff08;3&#xff09;\u91cd\u70b9\u6536\u96c6\u5668\u8be6\u89e3<\/h5>\n<h6 id=\"%E2%91%A0%20CMS%20%E6%94%B6%E9%9B%86%E5%99%A8%EF%BC%88%E4%BD%8E%E5%81%9C%E9%A1%BF%E9%A6%96%E9%80%89%EF%BC%89\">\u2460 CMS \u6536\u96c6\u5668&#xff08;\u4f4e\u505c\u987f\u9996\u9009&#xff09;<\/h6>\n<ul>\n<li>\u6838\u5fc3\u76ee\u6807&#xff1a;\u83b7\u53d6\u6700\u77ed\u56de\u6536\u505c\u987f\u65f6\u95f4&#xff0c;\u9002\u7528\u4e8e B\/S \u7cfb\u7edf\u3001\u4e92\u8054\u7f51\u5e94\u7528\u7b49\u5bf9\u54cd\u5e94\u901f\u5ea6\u654f\u611f\u7684\u573a\u666f\u3002<\/li>\n<li>\u8fd0\u4f5c\u6d41\u7a0b&#xff08;4 \u6b65&#xff09;&#xff1a;\n<li>\u521d\u59cb\u6807\u8bb0&#xff08;Initial Mark&#xff09;&#xff1a;\u6807\u8bb0 GC Roots \u76f4\u63a5\u5173\u8054\u7684\u5bf9\u8c61&#xff0c;\u901f\u5ea6\u5feb&#xff0c;\u9700 STW\u3002<\/li>\n<li>\u5e76\u53d1\u6807\u8bb0&#xff08;Concurrent Mark&#xff09;&#xff1a;\u904d\u5386\u5f15\u7528\u94fe&#xff0c;\u6807\u8bb0\u6240\u6709\u6b7b\u4ea1\u5bf9\u8c61&#xff0c;\u4e0e\u7528\u6237\u7ebf\u7a0b\u5e76\u53d1\u6267\u884c&#xff0c;\u65e0\u9700 STW\u3002<\/li>\n<li>\u91cd\u65b0\u6807\u8bb0&#xff08;Remark&#xff09;&#xff1a;\u4fee\u6b63\u5e76\u53d1\u6807\u8bb0\u671f\u95f4\u56e0\u7528\u6237\u7ebf\u7a0b\u6267\u884c\u5bfc\u81f4\u6807\u8bb0\u53d8\u52a8\u7684\u5bf9\u8c61&#xff0c;\u9700 STW&#xff08;\u505c\u987f\u65f6\u95f4\u77ed\u4e8e\u521d\u59cb\u6807\u8bb0&#xff09;\u3002<\/li>\n<li>\u5e76\u53d1\u6e05\u9664&#xff08;Concurrent Sweep&#xff09;&#xff1a;\u56de\u6536\u6b7b\u4ea1\u5bf9\u8c61&#xff0c;\u4e0e\u7528\u6237\u7ebf\u7a0b\u5e76\u53d1\u6267\u884c&#xff0c;\u65e0\u9700 STW\u3002<\/li>\n<\/li>\n<li>\u6838\u5fc3\u7f3a\u70b9&#xff1a;\n<li>CPU \u654f\u611f&#xff1a;\u5e76\u53d1\u9636\u6bb5\u5360\u7528 CPU \u8d44\u6e90&#xff0c;\u5bfc\u81f4\u5e94\u7528\u7a0b\u5e8f\u541e\u5410\u91cf\u4e0b\u964d&#xff08;\u9ed8\u8ba4 GC \u7ebf\u7a0b\u6570 &#061; (CPU \u6570 &#043; 3)\/4&#xff09;\u3002<\/li>\n<li>\u6d6e\u52a8\u5783\u573e&#xff1a;\u5e76\u53d1\u6e05\u9664\u9636\u6bb5\u7528\u6237\u7ebf\u7a0b\u4ecd\u4ea7\u751f\u65b0\u5783\u573e&#xff0c;\u65e0\u6cd5\u5728\u672c\u6b21 GC \u4e2d\u56de\u6536&#xff0c;\u9700\u9884\u7559\u5185\u5b58\u7a7a\u95f4&#xff08;\u907f\u514d OOM&#xff09;\u3002<\/li>\n<li>\u5185\u5b58\u788e\u7247&#xff1a;\u57fa\u4e8e\u6807\u8bb0 &#8211; \u6e05\u9664\u7b97\u6cd5&#xff0c;\u4ea7\u751f\u5927\u91cf\u788e\u7247&#xff0c;\u53ef\u80fd\u5bfc\u81f4\u63d0\u524d\u89e6\u53d1 Full GC\u3002<\/li>\n<\/li>\n<\/ul>\n<h6 id=\"%E2%91%A1%20G1%20%E6%94%B6%E9%9B%86%E5%99%A8%EF%BC%88%E5%85%A8%E5%8C%BA%E5%9F%9F%E9%A6%96%E9%80%89%EF%BC%89\">\u2461 G1 \u6536\u96c6\u5668&#xff08;\u5168\u533a\u57df\u9996\u9009&#xff09;<\/h6>\n<ul>\n<li>\u6838\u5fc3\u5b9a\u4f4d&#xff1a;\u9762\u5411\u670d\u52a1\u7aef\u5e94\u7528&#xff0c;\u65e8\u5728\u66ff\u4ee3 CMS&#xff0c;\u517c\u987e\u541e\u5410\u91cf\u548c\u4f4e\u505c\u987f&#xff0c;\u9002\u7528\u4e8e\u5927\u5806\u5185\u5b58\u573a\u666f&#xff08;\u5982 10GB \u4ee5\u4e0a&#xff09;\u3002<\/li>\n<li>\u6838\u5fc3\u7279\u6027&#xff1a;\n<li>\u5206\u533a\u6536\u96c6&#xff1a;\u5c06\u5806\u5212\u5206\u4e3a\u591a\u4e2a\u5927\u5c0f\u76f8\u7b49\u7684 Region&#xff08;\u533a\u57df&#xff09;&#xff0c;\u6bcf\u4e2a Region \u53ef\u52a8\u6001\u6807\u8bb0\u4e3a Eden\u3001Survivor\u3001Old\u3001Humongous&#xff08;\u5b58\u50a8\u5927\u5bf9\u8c61&#xff0c;\u8d85\u8fc7 Region \u5927\u5c0f 50%&#xff09;\u3002<\/li>\n<li>\u4f18\u5148\u56de\u6536&#xff1a;\u57fa\u4e8e \u201cGarbage First\u201d \u7b56\u7565&#xff0c;\u4f18\u5148\u56de\u6536\u5783\u573e\u6700\u591a\u7684 Region&#xff08;\u5783\u573e\u56de\u6536\u7387\u6700\u9ad8&#xff09;\u3002<\/li>\n<li>\u65e0\u5185\u5b58\u788e\u7247&#xff1a;\u6574\u4f53\u91c7\u7528\u6807\u8bb0 &#8211; \u6574\u7406\u7b97\u6cd5&#xff0c;\u5c40\u90e8&#xff08;Region \u4e4b\u95f4&#xff09;\u91c7\u7528\u590d\u5236\u7b97\u6cd5&#xff0c;\u56de\u6536\u540e\u81ea\u52a8\u538b\u7f29\u5185\u5b58\u3002<\/li>\n<li>\u53ef\u9884\u6d4b\u505c\u987f\u65f6\u95f4&#xff1a;\u901a\u8fc7\u53c2\u6570-XX:MaxGCPauseMillis\u8bbe\u7f6e\u6700\u5927\u505c\u987f\u65f6\u95f4&#xff0c;G1 \u4f1a\u52a8\u6001\u8c03\u6574\u56de\u6536 Region \u6570\u91cf&#xff0c;\u786e\u4fdd\u505c\u987f\u65f6\u95f4\u4e0d\u8d85\u6807\u3002<\/li>\n<\/li>\n<li>\u8fd0\u4f5c\u6d41\u7a0b&#xff08;4 \u6b65&#xff09;&#xff1a;\n<li>\u521d\u59cb\u6807\u8bb0&#xff1a;\u6807\u8bb0 GC Roots \u76f4\u63a5\u5173\u8054\u7684\u5bf9\u8c61&#xff0c;\u4e0e Minor GC \u540c\u6b65\u6267\u884c&#xff0c;\u9700 STW\u3002<\/li>\n<li>\u5e76\u53d1\u6807\u8bb0&#xff1a;\u904d\u5386\u5f15\u7528\u94fe&#xff0c;\u6807\u8bb0\u6b7b\u4ea1\u5bf9\u8c61&#xff0c;\u4e0e\u7528\u6237\u7ebf\u7a0b\u5e76\u53d1\u6267\u884c&#xff1b;\u540c\u65f6\u8ba1\u7b97\u6bcf\u4e2a Region \u7684\u5783\u573e\u56de\u6536\u7387\u3002<\/li>\n<li>\u6700\u7ec8\u6807\u8bb0&#xff08;Remark&#xff09;&#xff1a;\u4fee\u6b63\u5e76\u53d1\u6807\u8bb0\u671f\u95f4\u7684\u6807\u8bb0\u53d8\u52a8&#xff0c;\u91c7\u7528 SATB&#xff08;\u5feb\u7167\u539f\u5b50\u6027&#xff09;\u7b97\u6cd5&#xff0c;STW \u65f6\u95f4\u77ed\u3002<\/li>\n<li>\u7b5b\u9009\u56de\u6536&#xff08;Clean Up\/Copy&#xff09;&#xff1a;\u7b5b\u9009\u5783\u573e\u56de\u6536\u7387\u9ad8\u7684 Region&#xff0c;\u590d\u5236\u5b58\u6d3b\u5bf9\u8c61\u5230\u7a7a Region&#xff0c;\u6e05\u7a7a\u539f Region&#xff1b;\u4e0e Minor GC \u540c\u6b65\u6267\u884c&#xff0c;\u9700 STW\u3002<\/li>\n<\/li>\n<\/ul>\n<h4 id=\"4.%20%E4%B8%80%E4%B8%AA%E5%AF%B9%E8%B1%A1%E7%9A%84%E4%B8%80%E7%94%9F%EF%BC%88%E6%80%BB%E7%BB%93%EF%BC%89\">4. \u4e00\u4e2a\u5bf9\u8c61\u7684\u4e00\u751f&#xff08;\u603b\u7ed3&#xff09;<\/h4>\n<li>\u8bde\u751f&#xff1a;\u5bf9\u8c61\u5728\u65b0\u751f\u4ee3 Eden \u533a\u521b\u5efa\u3002<\/li>\n<li>\u65b0\u751f\u4ee3\u6d41\u8f6c&#xff1a;Eden \u533a\u6ee1\u89e6\u53d1 Minor GC&#xff0c;\u5b58\u6d3b\u5bf9\u8c61\u590d\u5236\u5230 Survivor \u533a&#xff08;S0\/S1&#xff09;&#xff0c;\u53cd\u590d\u6d41\u8f6c\u3002<\/li>\n<li>\u664b\u5347\u8001\u5e74\u4ee3&#xff1a;\u5bf9\u8c61\u5728 Survivor \u533a\u590d\u5236 15 \u6b21\u540e&#xff08;\u9ed8\u8ba4\u9608\u503c&#xff09;&#xff0c;\u6216\u4e3a\u5927\u5bf9\u8c61&#xff0c;\u664b\u5347\u5230\u8001\u5e74\u4ee3\u3002<\/li>\n<li>\u8001\u5e74\u4ee3\u5b58\u6d3b&#xff1a;\u5728\u8001\u5e74\u4ee3\u4e2d\u6301\u7eed\u5b58\u6d3b&#xff0c;\u7ecf\u5386\u591a\u6b21 Full GC\u3002<\/li>\n<li>\u6b7b\u4ea1&#xff1a;\u5f53\u5bf9\u8c61\u5230 GC Roots \u4e0d\u53ef\u8fbe&#xff0c;\u88ab\u6807\u8bb0\u4e3a\u6b7b\u4ea1\u5bf9\u8c61&#xff0c;\u6700\u7ec8\u88ab GC \u56de\u6536&#xff08;\u65b0\u751f\u4ee3\u590d\u5236\u7b97\u6cd5 \/ \u8001\u5e74\u4ee3\u6807\u8bb0 &#8211; \u6574\u7406\u7b97\u6cd5&#xff09;\u3002<\/li>\n<h3 id=\"%E4%B8%83%E3%80%81Java%20%E5%86%85%E5%AD%98%E6%A8%A1%E5%9E%8B%EF%BC%88JMM%EF%BC%89\">\u4e03\u3001Java \u5185\u5b58\u6a21\u578b&#xff08;JMM&#xff09;<\/h3>\n<p>JMM&#xff08;Java Memory Model&#xff09;\u662f JVM \u5b9a\u4e49\u7684\u5185\u5b58\u8bbf\u95ee\u89c4\u8303&#xff0c;\u7528\u4e8e\u5c4f\u853d\u4e0d\u540c\u786c\u4ef6\u548c\u64cd\u4f5c\u7cfb\u7edf\u7684\u5185\u5b58\u8bbf\u95ee\u5dee\u5f02&#xff0c;\u786e\u4fdd Java \u7a0b\u5e8f\u5728\u591a\u7ebf\u7a0b\u73af\u5883\u4e0b\u7684\u5e76\u53d1\u5b89\u5168\u6027&#xff08;\u539f\u5b50\u6027\u3001\u53ef\u89c1\u6027\u3001\u6709\u5e8f\u6027&#xff09;\u3002<\/p>\n<h4 id=\"1.%20%E6%A0%B8%E5%BF%83%E6%A6%82%E5%BF%B5%EF%BC%9A%E4%B8%BB%E5%86%85%E5%AD%98%E4%B8%8E%E5%B7%A5%E4%BD%9C%E5%86%85%E5%AD%98\">1. \u6838\u5fc3\u6982\u5ff5&#xff1a;\u4e3b\u5185\u5b58\u4e0e\u5de5\u4f5c\u5185\u5b58<\/h4>\n<p>JMM \u5b9a\u4e49\u4e86\u7ebf\u7a0b\u4e0e\u5185\u5b58\u7684\u4ea4\u4e92\u89c4\u5219&#xff0c;\u5c06\u5185\u5b58\u5206\u4e3a\u4e24\u7c7b&#xff1a;<\/p>\n<ul>\n<li>\u4e3b\u5185\u5b58&#xff1a;\u5b58\u50a8\u6240\u6709\u7ebf\u7a0b\u5171\u4eab\u7684\u53d8\u91cf&#xff08;\u5b9e\u4f8b\u5b57\u6bb5\u3001\u9759\u6001\u5b57\u6bb5\u3001\u6570\u7ec4\u5143\u7d20&#xff09;&#xff0c;\u662f\u7269\u7406\u5185\u5b58\u7684\u62bd\u8c61\u3002<\/li>\n<li>\u5de5\u4f5c\u5185\u5b58&#xff1a;\u6bcf\u4e2a\u7ebf\u7a0b\u79c1\u6709\u7684\u5185\u5b58\u533a\u57df&#xff0c;\u5b58\u50a8\u4e3b\u5185\u5b58\u53d8\u91cf\u7684\u526f\u672c\u62f7\u8d1d&#xff1b;\u7ebf\u7a0b\u5bf9\u53d8\u91cf\u7684\u6240\u6709\u64cd\u4f5c&#xff08;\u8bfb\u53d6\u3001\u8d4b\u503c&#xff09;\u5747\u5728\u5de5\u4f5c\u5185\u5b58\u4e2d\u6267\u884c&#xff0c;\u65e0\u6cd5\u76f4\u63a5\u8bbf\u95ee\u4e3b\u5185\u5b58\u3002<\/li>\n<\/ul>\n<h4 id=\"2.%20%E5%86%85%E5%AD%98%E9%97%B4%E4%BA%A4%E4%BA%92%E6%93%8D%E4%BD%9C%EF%BC%888%20%E7%A7%8D%E5%8E%9F%E5%AD%90%E6%93%8D%E4%BD%9C%EF%BC%89\">2. \u5185\u5b58\u95f4\u4ea4\u4e92\u64cd\u4f5c&#xff08;8 \u79cd\u539f\u5b50\u64cd\u4f5c&#xff09;<\/h4>\n<p>JMM \u5b9a\u4e49\u4e86 8 \u79cd\u539f\u5b50\u64cd\u4f5c&#xff0c;\u786e\u4fdd\u4e3b\u5185\u5b58\u4e0e\u5de5\u4f5c\u5185\u5b58\u4e4b\u95f4\u7684\u6570\u636e\u540c\u6b65&#xff0c;\u64cd\u4f5c\u9700\u6ee1\u8db3\u539f\u5b50\u6027\u3001\u4e0d\u53ef\u5206\u5272&#xff1a;<\/p>\n<ul>\n<li>lock&#xff08;\u9501\u5b9a&#xff09;&#xff1a;\u4f5c\u7528\u4e8e\u4e3b\u5185\u5b58\u53d8\u91cf&#xff0c;\u6807\u8bb0\u4e3a\u7ebf\u7a0b\u72ec\u5360\u72b6\u6001\u3002<\/li>\n<li>unlock&#xff08;\u89e3\u9501&#xff09;&#xff1a;\u4f5c\u7528\u4e8e\u4e3b\u5185\u5b58\u53d8\u91cf&#xff0c;\u91ca\u653e\u9501\u5b9a\u72b6\u6001&#xff0c;\u5141\u8bb8\u5176\u4ed6\u7ebf\u7a0b\u9501\u5b9a\u3002<\/li>\n<li>read&#xff08;\u8bfb\u53d6&#xff09;&#xff1a;\u4f5c\u7528\u4e8e\u4e3b\u5185\u5b58\u53d8\u91cf&#xff0c;\u5c06\u53d8\u91cf\u503c\u4f20\u8f93\u5230\u7ebf\u7a0b\u5de5\u4f5c\u5185\u5b58\u3002<\/li>\n<li>load&#xff08;\u8f7d\u5165&#xff09;&#xff1a;\u4f5c\u7528\u4e8e\u5de5\u4f5c\u5185\u5b58\u53d8\u91cf&#xff0c;\u5c06 read \u64cd\u4f5c\u83b7\u53d6\u7684\u53d8\u91cf\u503c\u5b58\u5165\u5de5\u4f5c\u5185\u5b58\u526f\u672c\u3002<\/li>\n<li>use&#xff08;\u4f7f\u7528&#xff09;&#xff1a;\u4f5c\u7528\u4e8e\u5de5\u4f5c\u5185\u5b58\u53d8\u91cf&#xff0c;\u5c06\u53d8\u91cf\u503c\u4f20\u9012\u7ed9\u6267\u884c\u5f15\u64ce&#xff08;\u5982\u8fd0\u7b97&#xff09;\u3002<\/li>\n<li>assign&#xff08;\u8d4b\u503c&#xff09;&#xff1a;\u4f5c\u7528\u4e8e\u5de5\u4f5c\u5185\u5b58\u53d8\u91cf&#xff0c;\u5c06\u6267\u884c\u5f15\u64ce\u7684\u7ed3\u679c\u8d4b\u7ed9\u53d8\u91cf\u526f\u672c\u3002<\/li>\n<li>store&#xff08;\u5b58\u50a8&#xff09;&#xff1a;\u4f5c\u7528\u4e8e\u5de5\u4f5c\u5185\u5b58\u53d8\u91cf&#xff0c;\u5c06\u53d8\u91cf\u503c\u4f20\u8f93\u5230\u4e3b\u5185\u5b58\u3002<\/li>\n<li>write&#xff08;\u5199\u5165&#xff09;&#xff1a;\u4f5c\u7528\u4e8e\u4e3b\u5185\u5b58\u53d8\u91cf&#xff0c;\u5c06 store \u64cd\u4f5c\u83b7\u53d6\u7684\u53d8\u91cf\u503c\u5b58\u5165\u4e3b\u5185\u5b58\u3002<\/li>\n<\/ul>\n<h4 id=\"3.%20JMM%20%E7%9A%84%E4%B8%89%E5%A4%A7%E6%A0%B8%E5%BF%83%E7%89%B9%E6%80%A7\">3. JMM \u7684\u4e09\u5927\u6838\u5fc3\u7279\u6027<\/h4>\n<p>\u5e76\u53d1\u7a0b\u5e8f\u6b63\u786e\u6267\u884c\u9700\u4fdd\u8bc1\u4e09\u5927\u7279\u6027&#xff0c;JMM \u901a\u8fc7\u4e0a\u8ff0\u64cd\u4f5c\u548c\u5173\u952e\u5b57&#xff08;volatile\u3001synchronized&#xff09;\u5b9e\u73b0&#xff1a;<\/p>\n<h5 id=\"%EF%BC%881%EF%BC%89%E5%8E%9F%E5%AD%90%E6%80%A7\">&#xff08;1&#xff09;\u539f\u5b50\u6027<\/h5>\n<ul>\n<li>\u5b9a\u4e49&#xff1a;\u4e00\u4e2a\u64cd\u4f5c\u6216\u591a\u4e2a\u64cd\u4f5c\u8981\u4e48\u5168\u90e8\u6267\u884c\u4e14\u4e0d\u88ab\u6253\u65ad&#xff0c;\u8981\u4e48\u5168\u90e8\u4e0d\u6267\u884c\u3002<\/li>\n<li>JMM \u4fdd\u8bc1&#xff1a;read\u3001load\u3001assign\u3001use\u3001store\u3001write \u7b49\u57fa\u672c\u64cd\u4f5c\u539f\u5b50\u6027&#xff1b;\u66f4\u5927\u8303\u56f4\u7684\u539f\u5b50\u6027&#xff08;\u5982i&#043;&#043;&#xff09;\u9700\u901a\u8fc7 synchronized\u6216java.util.concurrent.locks\u9501\u5b9e\u73b0\u3002<\/li>\n<li>\u793a\u4f8b&#xff1a;i&#043;&#043;\u5e76\u975e\u539f\u5b50\u64cd\u4f5c&#xff08;\u5206\u4e3a\u8bfb\u53d6 i\u3001i&#043;1\u3001\u8d4b\u503c\u7ed9 i \u4e09\u6b65&#xff09;&#xff0c;\u591a\u7ebf\u7a0b\u73af\u5883\u4e0b\u53ef\u80fd\u51fa\u73b0\u7ebf\u7a0b\u5b89\u5168\u95ee\u9898\u3002<\/li>\n<\/ul>\n<h5 id=\"%EF%BC%882%EF%BC%89%E5%8F%AF%E8%A7%81%E6%80%A7\">&#xff08;2&#xff09;\u53ef\u89c1\u6027<\/h5>\n<ul>\n<li>\u5b9a\u4e49&#xff1a;\u5f53\u4e00\u4e2a\u7ebf\u7a0b\u4fee\u6539\u5171\u4eab\u53d8\u91cf\u7684\u503c&#xff0c;\u5176\u4ed6\u7ebf\u7a0b\u80fd\u7acb\u5373\u611f\u77e5\u5230\u8be5\u4fee\u6539\u3002<\/li>\n<li>\u5b9e\u73b0\u65b9\u5f0f&#xff1a;\n<li>volatile&#xff1a;\u4fee\u9970\u7684\u53d8\u91cf\u4fee\u6539\u540e&#xff0c;\u4f1a\u7acb\u5373\u540c\u6b65\u5230\u4e3b\u5185\u5b58&#xff0c;\u5176\u4ed6\u7ebf\u7a0b\u8bfb\u53d6\u65f6\u76f4\u63a5\u4ece\u4e3b\u5185\u5b58\u52a0\u8f7d&#xff08;\u7981\u7528\u5de5\u4f5c\u5185\u5b58\u7f13\u5b58&#xff09;\u3002<\/li>\n<li>synchronized&#xff1a;\u89e3\u9501\u524d&#xff0c;\u7ebf\u7a0b\u9700\u5c06\u5de5\u4f5c\u5185\u5b58\u4e2d\u53d8\u91cf\u7684\u4fee\u6539\u540c\u6b65\u5230\u4e3b\u5185\u5b58&#xff1b;\u52a0\u9501\u65f6&#xff0c;\u7ebf\u7a0b\u6e05\u7a7a\u5de5\u4f5c\u5185\u5b58\u526f\u672c&#xff0c;\u4ece\u4e3b\u5185\u5b58\u91cd\u65b0\u52a0\u8f7d\u53d8\u91cf&#xff08;happen-before \u539f\u5219&#xff09;\u3002<\/li>\n<li>final&#xff1a;final \u4fee\u9970\u7684\u53d8\u91cf\u521d\u59cb\u5316\u5b8c\u6210\u540e&#xff0c;\u5176\u503c\u5bf9\u6240\u6709\u7ebf\u7a0b\u53ef\u89c1&#xff08;\u4e0d\u53ef\u4fee\u6539&#xff09;\u3002<\/li>\n<\/li>\n<\/ul>\n<h5 id=\"%EF%BC%883%EF%BC%89%E6%9C%89%E5%BA%8F%E6%80%A7\">&#xff08;3&#xff09;\u6709\u5e8f\u6027<\/h5>\n<ul>\n<li>\u5b9a\u4e49&#xff1a;\u7ebf\u7a0b\u5185\u64cd\u4f5c\u6309\u4ee3\u7801\u987a\u5e8f\u6267\u884c&#xff08;\u7ebf\u7a0b\u5185\u4e32\u884c&#xff09;&#xff1b;\u7ebf\u7a0b\u95f4\u89c2\u5bdf\u65f6&#xff0c;\u64cd\u4f5c\u53ef\u80fd\u65e0\u5e8f&#xff08;\u6307\u4ee4\u91cd\u6392\u5e8f\u3001\u5de5\u4f5c\u5185\u5b58\u4e0e\u4e3b\u5185\u5b58\u540c\u6b65\u5ef6\u8fdf&#xff09;\u3002<\/li>\n<li>\u6307\u4ee4\u91cd\u6392\u5e8f&#xff1a;\u7f16\u8bd1\u5668\u6216 CPU \u4e3a\u4f18\u5316\u6027\u80fd&#xff0c;\u5728\u4e0d\u5f71\u54cd\u5355\u7ebf\u7a0b\u6267\u884c\u7ed3\u679c\u7684\u524d\u63d0\u4e0b&#xff0c;\u8c03\u6574\u6307\u4ee4\u6267\u884c\u987a\u5e8f&#xff08;\u5982a&#061;1; b&#061;2\u53ef\u80fd\u88ab\u91cd\u6392\u4e3ab&#061;2; a&#061;1&#xff09;\u3002<\/li>\n<li>\u5b9e\u73b0\u65b9\u5f0f&#xff1a;\n<li>volatile&#xff1a;\u7981\u6b62\u6307\u4ee4\u91cd\u6392\u5e8f&#xff08;\u4fee\u9970\u7684\u53d8\u91cf\u524d\u540e\u7684\u6307\u4ee4\u4e0d\u53ef\u91cd\u6392&#xff09;\u3002<\/li>\n<li>synchronized&#xff1a;\u4fdd\u8bc1\u540c\u4e00\u65f6\u523b\u53ea\u6709\u4e00\u4e2a\u7ebf\u7a0b\u6267\u884c\u540c\u6b65\u5757&#xff0c;\u95f4\u63a5\u4fdd\u8bc1\u6709\u5e8f\u6027\u3002<\/li>\n<li>happen-before \u539f\u5219&#xff08;\u5148\u5929\u6709\u5e8f\u6027&#xff09;&#xff1a;\u65e0\u9700\u4efb\u4f55\u5173\u952e\u5b57&#xff0c;JMM \u9ed8\u8ba4\u4fdd\u8bc1\u7684\u6709\u5e8f\u6027&#xff0c;\u5305\u62ec&#xff1a;\n<ul>\n<li>\u7a0b\u5e8f\u6b21\u5e8f\u89c4\u5219&#xff1a;\u7ebf\u7a0b\u5185\u4ee3\u7801\u6309\u4e66\u5199\u987a\u5e8f\u6267\u884c\u3002<\/li>\n<li>\u9501\u5b9a\u89c4\u5219&#xff1a;unlock \u64cd\u4f5c\u5148\u884c\u53d1\u751f\u4e8e\u540e\u9762\u5bf9\u540c\u4e00\u9501\u7684 lock \u64cd\u4f5c\u3002<\/li>\n<li>volatile \u53d8\u91cf\u89c4\u5219&#xff1a;\u5bf9 volatile \u53d8\u91cf\u7684\u5199\u64cd\u4f5c\u5148\u884c\u53d1\u751f\u4e8e\u8bfb\u64cd\u4f5c\u3002<\/li>\n<li>\u4f20\u9012\u89c4\u5219&#xff1a;A \u5148\u884c\u53d1\u751f\u4e8e B&#xff0c;B \u5148\u884c\u53d1\u751f\u4e8e C&#xff0c;\u5219 A \u5148\u884c\u53d1\u751f\u4e8e C\u3002<\/li>\n<li>\u7ebf\u7a0b\u542f\u52a8\u89c4\u5219&#xff1a;Thread.start () \u5148\u884c\u53d1\u751f\u4e8e\u7ebf\u7a0b\u5185\u6240\u6709\u64cd\u4f5c\u3002<\/li>\n<li>\u7ebf\u7a0b\u4e2d\u65ad\u89c4\u5219&#xff1a;interrupt () \u5148\u884c\u53d1\u751f\u4e8e\u7ebf\u7a0b\u68c0\u6d4b\u5230\u4e2d\u65ad\u4e8b\u4ef6\u3002<\/li>\n<li>\u7ebf\u7a0b\u7ec8\u7ed3\u89c4\u5219&#xff1a;\u7ebf\u7a0b\u5185\u6240\u6709\u64cd\u4f5c\u5148\u884c\u53d1\u751f\u4e8e\u7ebf\u7a0b\u7ec8\u6b62\u68c0\u6d4b&#xff08;\u5982 join ()&#xff09;\u3002<\/li>\n<li>\u5bf9\u8c61\u7ec8\u7ed3\u89c4\u5219&#xff1a;\u5bf9\u8c61\u521d\u59cb\u5316\u5b8c\u6210\u5148\u884c\u53d1\u751f\u4e8e finalize () \u65b9\u6cd5\u3002<\/li>\n<\/ul>\n<\/li>\n<\/li>\n<\/ul>\n<h4 id=\"4.%20volatile%20%E5%85%B3%E9%94%AE%E5%AD%97%E8%AF%A6%E8%A7%A3\">4. volatile \u5173\u952e\u5b57\u8be6\u89e3<\/h4>\n<p>volatile\u662f JMM \u63d0\u4f9b\u7684\u6700\u8f7b\u91cf\u7ea7\u540c\u6b65\u673a\u5236&#xff0c;\u4ec5\u4fdd\u8bc1\u53ef\u89c1\u6027\u548c\u6709\u5e8f\u6027&#xff0c;\u4e0d\u4fdd\u8bc1\u539f\u5b50\u6027\u3002<\/p>\n<h5 id=\"%EF%BC%881%EF%BC%89%E6%A0%B8%E5%BF%83%E7%89%B9%E6%80%A7\">&#xff08;1&#xff09;\u6838\u5fc3\u7279\u6027<\/h5>\n<li>\u53ef\u89c1\u6027&#xff1a;volatile \u53d8\u91cf\u7684\u4fee\u6539\u4f1a\u7acb\u5373\u540c\u6b65\u5230\u4e3b\u5185\u5b58&#xff0c;\u5176\u4ed6\u7ebf\u7a0b\u8bfb\u53d6\u65f6\u76f4\u63a5\u4ece\u4e3b\u5185\u5b58\u52a0\u8f7d&#xff0c;\u907f\u514d\u7f13\u5b58\u4e0d\u4e00\u81f4\u3002<\/li>\n<li>\u7981\u6b62\u6307\u4ee4\u91cd\u6392\u5e8f&#xff1a;volatile \u53d8\u91cf\u524d\u540e\u7684\u6307\u4ee4\u4e0d\u53ef\u91cd\u6392&#xff0c;\u786e\u4fdd\u4ee3\u7801\u6267\u884c\u987a\u5e8f\u4e0e\u9884\u671f\u4e00\u81f4\u3002<\/li>\n<h5 id=\"%EF%BC%882%EF%BC%89%E4%B8%8D%E4%BF%9D%E8%AF%81%E5%8E%9F%E5%AD%90%E6%80%A7%E7%9A%84%E7%A4%BA%E4%BE%8B\">&#xff08;2&#xff09;\u4e0d\u4fdd\u8bc1\u539f\u5b50\u6027\u7684\u793a\u4f8b<\/h5>\n<p>public class VolatileAtomicTest {<br \/>\n    public static volatile int num &#061; 0;<br \/>\n    public static void increase() {<br \/>\n        num&#043;&#043;; \/\/ \u975e\u539f\u5b50\u64cd\u4f5c&#xff0c;volatile\u65e0\u6cd5\u4fdd\u8bc1<br \/>\n    }<br \/>\n    public static void main(String[] args) {<br \/>\n        Thread[] threads &#061; new Thread[10];<br \/>\n        for (int i &#061; 0; i &lt; 10; i&#043;&#043;) {<br \/>\n            threads[i] &#061; new Thread(() -&gt; {<br \/>\n                for (int j &#061; 0; j &lt; 100; j&#043;&#043;) {<br \/>\n                    increase();<br \/>\n                }<br \/>\n            });<br \/>\n            threads[i].start();<br \/>\n        }<br \/>\n        while (Thread.activeCount() &gt; 2) {<br \/>\n            Thread.yield();<br \/>\n        }<br \/>\n        System.out.println(num); \/\/ \u7ed3\u679c\u5c0f\u4e8e1000&#xff0c;\u5b58\u5728\u7ebf\u7a0b\u5b89\u5168\u95ee\u9898<br \/>\n    }<br \/>\n}<\/p>\n<ul>\n<li>\u539f\u56e0&#xff1a;num&#043;&#043;\u5206\u4e3a\u8bfb\u53d6 num\u3001num&#043;1\u3001\u8d4b\u503c\u7ed9 num \u4e09\u6b65&#xff0c;volatile \u4ec5\u4fdd\u8bc1\u8bfb\u53d6\u65f6\u83b7\u53d6\u6700\u65b0\u503c&#xff0c;\u4f46\u8fd0\u7b97\u8fc7\u7a0b\u4e2d\u53ef\u80fd\u88ab\u5176\u4ed6\u7ebf\u7a0b\u4fee\u6539&#xff0c;\u5bfc\u81f4\u7ed3\u679c\u8986\u76d6\u3002<\/li>\n<\/ul>\n<h5 id=\"%EF%BC%883%EF%BC%89volatile%20%E7%9A%84%E9%80%82%E7%94%A8%E5%9C%BA%E6%99%AF\">&#xff08;3&#xff09;volatile \u7684\u9002\u7528\u573a\u666f<\/h5>\n<p>\u9700\u6ee1\u8db3\u4ee5\u4e0b\u6761\u4ef6\u4e4b\u4e00&#xff1a;<\/p>\n<li>\u8fd0\u7b97\u7ed3\u679c\u4e0d\u4f9d\u8d56\u53d8\u91cf\u5f53\u524d\u503c&#xff08;\u5982\u5e03\u5c14\u6807\u5fd7\u4f4d&#xff09;\u3002<\/li>\n<li>\u4ec5\u5355\u4e00\u7ebf\u7a0b\u4fee\u6539\u53d8\u91cf&#xff0c;\u5176\u4ed6\u7ebf\u7a0b\u8bfb\u53d6\u3002<\/li>\n<ul>\n<li>\u793a\u4f8b&#xff08;\u6b63\u786e\u573a\u666f&#xff09;&#xff1a; volatile boolean shutdownRequested;<br \/>\npublic void shutdown() {<br \/>\n    shutdownRequested &#061; true; \/\/ \u5355\u4e00\u7ebf\u7a0b\u4fee\u6539<br \/>\n}<br \/>\npublic void work() {<br \/>\n    while (!shutdownRequested) { \/\/ \u591a\u7ebf\u7a0b\u8bfb\u53d6<br \/>\n        \/\/ \u6267\u884c\u4efb\u52a1<br \/>\n    }<br \/>\n}\n <\/li>\n<\/ul>\n<h5 id=\"%EF%BC%884%EF%BC%89%E7%A6%81%E6%AD%A2%E6%8C%87%E4%BB%A4%E9%87%8D%E6%8E%92%E5%BA%8F%E7%9A%84%E4%BD%9C%E7%94%A8\">&#xff08;4&#xff09;\u7981\u6b62\u6307\u4ee4\u91cd\u6392\u5e8f\u7684\u4f5c\u7528<\/h5>\n<ul>\n<li>\u793a\u4f8b&#xff1a; \/\/ x\u3001y\u4e3a\u975evolatile\u53d8\u91cf&#xff0c;flag\u4e3avolatile\u53d8\u91cf<br \/>\nx &#061; 2; \/\/ \u8bed\u53e51<br \/>\ny &#061; 0; \/\/ \u8bed\u53e52<br \/>\nflag &#061; true; \/\/ \u8bed\u53e53<br \/>\nx &#061; 4; \/\/ \u8bed\u53e54<br \/>\ny &#061; -1; \/\/ \u8bed\u53e55\n <\/li>\n<li>\u89c4\u5219&#xff1a;\u8bed\u53e5 3&#xff08;volatile \u5199&#xff09;\u4e0d\u80fd\u91cd\u6392\u5230\u8bed\u53e5 1\u30012 \u4e4b\u524d&#xff0c;\u4e5f\u4e0d\u80fd\u91cd\u6392\u5230\u8bed\u53e5 4\u30015 \u4e4b\u540e&#xff1b;\u8bed\u53e5 1\u30012 \u4e4b\u95f4&#xff0c;\u8bed\u53e5 4\u30015 \u4e4b\u95f4\u53ef\u91cd\u6392\u3002<\/li>\n<li>\u610f\u4e49&#xff1a;\u786e\u4fdd\u6267\u884c\u5230\u8bed\u53e5 3 \u65f6&#xff0c;\u8bed\u53e5 1\u30012 \u7684\u4fee\u6539\u5df2\u5b8c\u6210\u4e14\u53ef\u89c1&#xff0c;\u907f\u514d\u591a\u7ebf\u7a0b\u73af\u5883\u4e0b\u56e0\u91cd\u6392\u5bfc\u81f4\u7684\u903b\u8f91\u9519\u8bef\u3002<\/li>\n<\/ul>\n<h4 id=\"5.%20%E5%8F%8C%E9%87%8D%E6%A3%80%E6%9F%A5%E9%94%81%E5%AE%9A%E5%8D%95%E4%BE%8B%E6%A8%A1%E5%BC%8F%EF%BC%88volatile%20%E5%BA%94%E7%94%A8%EF%BC%89\">5. \u53cc\u91cd\u68c0\u67e5\u9501\u5b9a\u5355\u4f8b\u6a21\u5f0f&#xff08;volatile \u5e94\u7528&#xff09;<\/h4>\n<h5 id=\"%EF%BC%881%EF%BC%89%E9%97%AE%E9%A2%98%E4%BB%A3%E7%A0%81%EF%BC%88%E6%9C%AA%E7%94%A8%20volatile%EF%BC%89\">&#xff08;1&#xff09;\u95ee\u9898\u4ee3\u7801&#xff08;\u672a\u7528 volatile&#xff09;<\/h5>\n<p>public class Singleton {<br \/>\n    private static Singleton instance &#061; null;<br \/>\n    private Singleton() {}<br \/>\n    public static Singleton getInstance() {<br \/>\n        if (instance &#061;&#061; null) { \/\/ \u7b2c\u4e00\u6b21\u68c0\u67e5<br \/>\n            synchronized (Singleton.class) { \/\/ \u52a0\u9501<br \/>\n                if (instance &#061;&#061; null) { \/\/ \u7b2c\u4e8c\u6b21\u68c0\u67e5<br \/>\n                    instance &#061; new Singleton(); \/\/ \u975e\u539f\u5b50\u64cd\u4f5c<br \/>\n                }<br \/>\n            }<br \/>\n        }<br \/>\n        return instance;<br \/>\n    }<br \/>\n}<\/p>\n<ul>\n<li>\u95ee\u9898&#xff1a;instance &#061; new Singleton()\u5206\u4e3a\u4e09\u6b65&#xff1a;1. \u5206\u914d\u5185\u5b58&#xff1b;2. \u521d\u59cb\u5316\u6210\u5458\u53d8\u91cf&#xff1b;3. \u8d4b\u503c\u7ed9 instance&#xff08;instance \u975e null&#xff09;\u3002JIT \u7f16\u8bd1\u53ef\u80fd\u91cd\u6392\u4e3a 1\u21923\u21922&#xff0c;\u5bfc\u81f4\u7ebf\u7a0b B \u5728\u7b2c\u4e8c\u6b21\u68c0\u67e5\u65f6\u770b\u5230 instance \u975e null&#xff0c;\u4f46\u672a\u521d\u59cb\u5316\u5b8c\u6210&#xff0c;\u4f7f\u7528\u65f6\u629b\u51fa\u5f02\u5e38\u3002<\/li>\n<\/ul>\n<h5 id=\"%EF%BC%882%EF%BC%89%E4%BF%AE%E5%A4%8D%E6%96%B9%E6%A1%88%EF%BC%88volatile%20%E4%BF%AE%E9%A5%B0%20instance%EF%BC%89\">&#xff08;2&#xff09;\u4fee\u590d\u65b9\u6848&#xff08;volatile \u4fee\u9970 instance&#xff09;<\/h5>\n<p>public class Singleton {<br \/>\n    private volatile static Singleton instance &#061; 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