Java中9种常见的CMS GC问题分析与解决

{"type":"doc","content":[{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"1. 写在前面"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"本文主要针对 Hotspot VM 中“CMS + ParNew”组合的一些使用场景进行总结。重点通过部分源码对根因进行分析以及对排查方法进行总结，排查过程会省略较多。另外，本文专业术语较多，有一定的阅读门槛，如未介绍清楚，还请自行查阅相关材料。"}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"本文总字数 2 万左右（不包含代码片段），整体阅读时间约 30min ，文章较长，可以选择你感兴趣的场景进行研究。"}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https:\/\/static001.infoq.cn\/resource\/image\/58\/9d\/58b130fe50c3e7c5d05df4af43479e9d.png","alt":null,"title":null,"style":null,"href":null,"fromPaste":true,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"1.1 引言"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"自 Sun 发布 Java 语言以来，开始使用 GC 技术来进行内存自动管理，避免了手动管理带来的悬挂指针（Dangling Pointer）问题，很大程度上提升了开发效率，从此 GC 技术也一举成名。GC 有着非常悠久的历史，1960 年有着“Lisp 之父”和“人工智能之父”之称的 John McCarthy 就在论文中发布了 GC 算法，60 年以来， GC 技术的发展也突飞猛进，但不管是多么前沿的收集器也都是基于三种基本算法的组合或应用，也就是说 GC 要解决的根本问题这么多年一直都没有变过。笔者认为，在不太远的将来， GC 技术依然不会过时，比起日新月异的新技术，GC 这门古典技术更值得我们学习。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}}]}