1 /**
 2  * java堆溢出demo
 3  * JVM参数：-Xms20m -Xmx20m -XX:+HeapDumpOnOutOfMemoryError
 4  * Created by chenjunyi on 2018/4/25.
 5  */
 6 public class HeapOOM {
 7 
 8     static class OOMObject {
 9     }
10 
11     public static void main(String[] args) {
12         List<OOMObject> list = new ArrayList<>();
13         //不断创建新对象，使得Heap溢出
14         while (true) {
15             list.add(new OOMObject());
16         }
17     }
18 
19 }

1 java.lang.OutOfMemoryError: Java heap space

1 //使用StringBuilder在堆上创建字符串abc，再使用intern将其放入运行时常量池
2 String str = new StringBuilder("abc");
3 str.intern();
4 //直接使用字符串字面量xyz，其被放入运行时常量池
5 String str2 = "xyz";

 1 /**
 2  * java方法区溢出OutOfMemoryError（JVM参数适用于JDK1.6之前，借助CGLIB）
 3  * JVM参数：-XX:PermSize=10M -XX:MaxPermSize=10M
 4  * Created by chenjunyi on 2018/4/26.
 5  */
 6 public class JavaMethodAreaOOM {
 7 
 8     public static void main(String[] args) {
 9         while (true) {
10             Enhancer enhancer = new Enhancer();
11             enhancer.setSuperclass(OOMObject.class);
12             enhancer.setUseCache(false);
13             enhancer.setCallback((MethodInterceptor) (o, method, objects, methodProxy) -> methodProxy.invokeSuper(objects, args));
14             enhancer.create();
15         }
16     }
17 
18     static class OOMObject {
19     }
20 
21 }

1 Caused by: java.lang.OutOfMemoryError: PermGen space
2   at java.lang.ClassLoader.defineClass1(Native Method)
3   ···