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此时，空闲区间已经与活动区间交换，而垃圾对象现在已经全部留在了原来的活动区间，也就是现在的空闲区间。事实上，在活动区间转换为空间区间的同时，垃圾对象已经被一次性全部回收。","attrs":{}}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/ab/ab1f07e29f1e2bb42e9a080921e8c6da.png","alt":"image-20210205175603999","title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"标记整理算法","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"标记整理算法与标记清除算法很相似，也是分为两个阶段：标记和整理，。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"codeinline","content":[{"type":"text","text":"标记","attrs":{}}],"marks":[{"type":"color","attrs":{"color":"#1394d8","name":"user"}}],"attrs":{}},{"type":"text","text":"：它的第一个阶段与标记/清除算法是一模一样的，均是遍历GC 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Survivor区，然后清空eden区。当To Survivor区也存放满了时，则将Eden区和To Survivor区存活对象复制到From Survivor区，然后清空Eden和这个From Survivor区，此时To Survivor区为空，然后将To Survivor区和From Survivor区交换，即保持From Survivor区为空， 如此往复。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"当From Survivor区不足以存放 Eden区和To Survivor区的存活对象时，就将存活对象直接存放到老年代。若是老年代也满了就会触发一次Full GC，也就是新生代、老年代都进行回收。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"一般情况下，新生代发生的GC也叫做Minor 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等，在这种时候需要设置一个比较大的永久代空间来存放这些运行过程中新增的类。在JDK1.8之前，永久代称方法区，在JDK1.8后，永久代被称为元空间。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"堆结构中的不同分区中的算法选择","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"事实上，JVM对堆中的不同区域（新生代和老年代）采用不同的算法。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"新生代比较适合复制算法，新生代有Eden、From Survivor和To Survivor三个区，因为Eden区中对象会被复制到To Survivor，且From Survivor和To 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