JVM【一】

最新推荐文章于 2024-02-04 18:42:44 发布

2YSP

最新推荐文章于 2024-02-04 18:42:44 发布

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分类专栏： JVM 文章标签：内存溢出 JVM

本文链接：https://blog.youkuaiyun.com/stupid_Java_learner/article/details/62940732

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package cn.sp.test03;

import java.util.ArrayList;
import java.util.List;
/**
 * JVM堆内存溢出
 * @author 2YSP
 *
 */
public class TestOOM {
	static class OOMObject{
		
	}
	public static void main(String[] args) {
		List<OOMObject> list=new ArrayList<OOMObject>();
		while(true){
			
			list.add(new OOMObject());
		}
	}
}

当程序不断的new一个对象，GC却来不及回收的时候，就会造成内存溢出。抛出如下异常。

java.lang.OutOfMemoryError: Java heap space
Dumping heap to java_pid8292.hprof ...
Heap dump file created [27869904 bytes in 0.155 secs]
Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
	at java.util.Arrays.copyOf(Unknown Source)
	at java.util.Arrays.copyOf(Unknown Source)
	at java.util.ArrayList.grow(Unknown Source)
	at java.util.ArrayList.ensureExplicitCapacity(Unknown Source)
	at java.util.ArrayList.ensureCapacityInternal(Unknown Source)
	at java.util.ArrayList.add(Unknown Source)
	at cn.sp.test03.TestOOM.main(TestOOM.java:18)

package cn.sp.test03;
/**
 * 虚拟机栈溢出
 * @author 2YSP
 *
 */
public class TestOOM2 {
	static int stackIndex = 0;
	
	public void testStackOverFlow(){
		stackIndex++;
		/*int str = 12;
		int str2 = 12;
		int str3 = 12;
		int str4 = 12;
		int str5 = 12;
		int str6 = 12;
		int str7 = 12;
		int str8 = 12;*/

		testStackOverFlow();
	}
	public static void main(String[] args) throws Throwable {
		try {
			TestOOM2 oom=new TestOOM2();
			oom.testStackOverFlow();
		} catch (Throwable e) {
			System.out.println("堆栈深度(迭代次数):"+stackIndex);
			throw e;
		}
		
	}

}

一个方法无限调用自身的话，就会栈溢出，同时抛出以下异常。

堆栈深度(迭代次数):984
Exception in thread "main" java.lang.StackOverflowError
	at cn.sp.test03.TestOOM2.testStackOverFlow(TestOOM2.java:11)
	at cn.sp.test03.TestOOM2.testStackOverFlow(TestOOM2.java:21)
	at cn.sp.test03.TestOOM2.testStackOverFlow(TestOOM2.java:21)
	at cn.sp.test03.TestOOM2.testStackOverFlow(TestOOM2.java:21)
	at cn.sp.test03.TestOOM2.testStackOverFlow(TestOOM2.java:21)

如果我们把注释部分去掉，再运行一次就会发现，栈深度更少了，这是因为变量也占用了内存。

堆栈深度(迭代次数):577
Exception in thread "main" java.lang.StackOverflowError
	at cn.sp.test03.TestOOM2.testStackOverFlow(TestOOM2.java:11)
	at cn.sp.test03.TestOOM2.testStackOverFlow(TestOOM2.java:21)
	at cn.sp.test03.TestOOM2.testStackOverFlow(TestOOM2.java:21)
	at cn.sp.test03.TestOOM2.testStackOverFlow(TestOOM2.java:21)
	at cn.sp.test03.TestOOM2.testStackOverFlow(TestOOM2.java:21)
	at cn.sp.test03.TestOOM2.testStackOverFlow(TestOOM2.java:21)