JVM初体验

Posted 2022-12-23 superlsj

一、设计堆内存溢出异常：OutOfMemoryError：

1 public class Main 
2     public static void main(String[] args) 
3         List<Demo> list = new ArrayList<>();
4         while(true) 
5             list.add(new Demo());
6         
7     
8 

JVM参数：-XX:+HeapOnOutOfMemoryError   ：到处内存溢出的堆信息（hprof文件）

执行后报错：

java.lang.OutOfMemoryError: Java heap space
Dumping heap to java_pid15804.hprof ...
Heap dump file created [28024160 bytes in 0.082 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 com.qlu.test1.Main.main(Main.java:10)

查看文件：文件保存在项目文件夹中，但是要查看其中内容，你需要借助Eclipse Memory Analyzer工具。