（转）JVM各种内存溢出是否产生dump

     对于java的内存溢出，如果配置-XX:+HeapDumpOnOutOfMemoryError，很明确的知道堆内存溢出时会生成dump文件。但永久代内存溢出不明确是否会生成，今天来做一个实验：

永久代内存溢出，有dump文件。JVM的参数是-XX:PermSize=10m  -XX:MaxPermSize=10m   -XX:+HeapDumpOnOutOfMemoryError

1.  
   import java.util.ArrayList;
2.  
   import java.util.List;
3.  
   public class PermPoolOOM{
4.  
   public static void main(String[] args){
5.  
   List list = new ArrayList();
6.  
   int i = 0;
7.  
   while(true){
8.  
   list.add(String.valueOf(i++).intern());
9.  
   }
10.  
    }
11.  
    }

java.lang.OutOfMemoryError: PermGen space
Dumping heap to java_pid8900.hprof ...
Heap dump file created [17009938 bytes in 0.336 secs]
Exception in thread "main" java.lang.OutOfMemoryError: PermGen space
at java.lang.String.intern(Native Method)
at PermPoolOOM.main(PermPoolOOM.java:8)

方法区溢出，有dump文件。需要下载cglib-full-2.0.1.jar，JVM参数设置：-XX:PermSize=10m  -XX:MaxPermSize=10m   -XX:+HeapDumpOnOutOfMemoryError

1.  
   import java.lang.reflect.Method;
2.  
   import net.sf.cglib.proxy.Enhancer;
3.  
   import net.sf.cglib.proxy.MethodInterceptor;
4.  
   import net.sf.cglib.proxy.MethodProxy;
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(new MethodInterceptor() {
14.  
    public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable {
15.  
    return proxy.invokeSuper(obj, args);
16.  
    }
17.  
    });
18.  
    enhancer.create();
19.  
    }
20.  
    }
21.  
    static class OOMObject {
22.  
     
23.  
    }
24.  
    }

java.lang.OutOfMemoryError: PermGen space
Dumping heap to java_pid11000.hprof ...
Heap dump file created [6752989 bytes in 0.075 secs]
Exception in thread "main" net.sf.cglib.core.CodeGenerationException: java.lang.reflect.InvocationTargetException-->null
at net.sf.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:208)
at net.sf.cglib.proxy.Enhancer.createHelper(Enhancer.java:406)
at net.sf.cglib.proxy.Enhancer.create(Enhancer.java:318)
at JavaMethodAreaOOM.main(JavaMethodAreaOOM.java:21)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.sf.cglib.core.ReflectUtils.defineClass(ReflectUtils.java:411)
at net.sf.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:195)
... 3 more
Caused by: java.lang.OutOfMemoryError: PermGen space
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(Unknown Source)
at java.lang.ClassLoader.defineClass(Unknown Source)
... 8 more

直接内存溢出，没有dump文件。JVM参数配置：-XX:PermSize=10m  -XX:MaxPermSize=10m   -XX:+HeapDumpOnOutOfMemoryError  -XX:MaxDirectMemorySize=10M

1.  
   import java.lang.reflect.Field;
2.  
   import sun.misc.Unsafe;
3.  
    
4.  
   public class DirectMemoryOOM{
5.  
   private static final int _1MB = 1024* 1024 * 1024;
6.  
   public static void main(String[] args) throws Exception{
7.  
   Field unsafeField = Unsafe.class.getDeclaredFields()[0];
8.  
   unsafeField.setAccessible(true);
9.  
   Unsafe unsafe = (Unsafe) unsafeField.get(null);
10.  
    while(true){
11.  
    //unsafe直接想操作系统申请内存
12.  
    unsafe.allocateMemory(_1MB);
13.  
    }
14.  
    }
15.  
    }

Exception in thread "main" java.lang.OutOfMemoryError
at sun.misc.Unsafe.allocateMemory(Native Method)
at com.comtop.DirectMemoryOOM.main(DirectMemoryOOM.java:15)

栈内存溢出，没有dump文件。JVM参数设置:-Xss128k

1.  
   public class JavaVMStackOF{
2.  
   int stackLength = 1;
3.  
   public void stackLeak(){
4.  
   stackLength++;
5.  
   stackLeak();
6.  
   }
7.  
   public static void main(String[] args){
8.  
   JavaVMStackOF oom = new JavaVMStackOF();
9.  
   oom.stackLeak();
10.  
    }
11.  
    }

Exception in thread "main" java.lang.StackOverflowError
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:6)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)
at JavaVMStackOF.stackLeak(JavaVMStackOF.java:7)