模拟OOM及DecdLock实践

MMODemo.java

 

package dingchd;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;

import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;

public class MMODemo {

	StackOverFlowMMO stackmmo;
	DirectMMO directmmo;
	HeapMMO heapmmo;
	ArrayLimitMMO almmo;
	ThreadLimitMMO threadmmo;
	PermGenMMO pergemmmo;

	MMODemo() {
		stackmmo = new StackOverFlowMMO();
		directmmo = new DirectMMO();
		heapmmo = new HeapMMO();
		almmo = new ArrayLimitMMO();
		threadmmo = new ThreadLimitMMO();
		pergemmmo = new PermGenMMO();
	}

	public void displayDirect() {
		directmmo.display();
	}

	public void displayStack() {
		stackmmo.display();
	}

	public void displayHEAP() {
		heapmmo.display();
	}

	public void displayArryaLimit() {
		almmo.display();
	}

	public void displayThreadLimit() throws InterruptedException {
		threadmmo.display();
	}

	public void displayPermGen() throws IllegalArgumentException, Exception,
			Throwable {
		pergemmmo.display();
	}

	class DirectMMO {
		public void display() {
			List<ByteBuffer> list = new ArrayList();
			int size = 1000;
			int count = 0;
			while (true) {
				ByteBuffer buf = ByteBuffer.allocateDirect(size);
				for (int i = 0; i < size; i++) {
					int j = 1;
					buf.put((byte) j);
				}
				list.add(buf);
				count++;
				System.out.println("buffer direct allocate is " + count * size);
			}
		}
	}

	class StackOverFlowMMO {
		int lvl;

		StackOverFlowMMO() {
			lvl = 0;
		}

		public void display() {
			lvl = 0;
			func();
		}

		public void func() {
			++lvl;
			System.out.println("lvl " + lvl);
			func();
		}
	}

	class HeapMMO {

		public void display() {
			Integer a[] = new Integer[100000000];
		}
	}

	class ArrayLimitMMO {
		public void display() {
			System.out.println("Integer.MAX_VALUE is " + Integer.MAX_VALUE
					+ "\r\n");
			int[] pos = new int[Integer.MAX_VALUE - 1];
		}
	}

	class PermGenMMO {
		Helloworld loader = new Helloworld();

		// List<Object> list = new ArrayList();
		public void display() throws IllegalArgumentException, Exception,
				Throwable {

			int index = 0;
			int count = 0;
			while (true) {

				try {
					loader.createClass(index);
					loader.loadClass(index);
				} catch (IllegalAccessException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				} catch (IllegalArgumentException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				} catch (Exception e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
				// System.out.println(System.getProperty(null));
				count++;
				index++;
				if (count > 10)
					break;

			}

		}

		// 动态创建一个类
		class Helloworld extends ClassLoader implements Opcodes {
			public void createClass(int index) throws IOException,
					IllegalAccessException, IllegalArgumentException,
					Exception, Throwable {

				String name = "Example" + index;
				// System.out.println(name);
				ClassWriter cw = new ClassWriter(0);
				MethodVisitor mv;
				cw.visit(V1_1, ACC_PUBLIC, name, null, "java/lang/Object", null);

				for (int i = 0; i < 10000; i++) {
					String fun = "fun" + i;
					mv = cw.visitMethod(ACC_PUBLIC, fun, "()V", null, null);
					mv.visitCode();
					mv.visitFieldInsn(GETSTATIC, "java/lang/System", "out",
							"Ljava/io/PrintStream;");
					mv.visitLdcInsn("hello");
					mv.visitMethodInsn(INVOKEVIRTUAL, "java/io/PrintStream",
							"println", "(Ljava/lang/String;)V");
					mv.visitInsn(RETURN);
					mv.visitMaxs(2, 1);
					mv.visitEnd();
				}

				// gets the bytecode of the Example class, and loads it
				// dynamically
				byte[] code = cw.toByteArray();

				File directory = new File("");
				FileOutputStream fos = new FileOutputStream(name + ".class");
				fos.write(code);
				fos.close();

				// Class<?> exampleClass = loader.defineClass("Example"+index,
				// code, 0, code.length);

				// uses the dynamically generated class to print 'Helloworld'
				// exampleClass.getMethods()[0].invoke(null, new Object[] { null
				// });

			}

			public void loadClass(int index) throws ClassNotFoundException,
					InstantiationException, IllegalAccessException {
				String name = "Example" + index;

				Class a = Class.forName(name, true, this.getClass()
						.getClassLoader());
				// System.out.println("load "+name+".class");

			}
		}

	}

	class ThreadLimitMMO {
		List<Thread> list = new ArrayList();
		int count = 0;
		Long cur;
		Object lock = new Object();

		public void display() throws InterruptedException {
			System.out.println("-Xss = 128m");
			while (true) {
				Long cur = new Long(System.currentTimeMillis());

				Thread t = new Thread(cur.toString()) {
					@Override
					public void run() {
						int index = 0;
						synchronized (lock) {
							index = count;
							count++;
						}

						System.out.println(Thread.currentThread().getName()
								+ "create,index" + index);
						try {
							Thread.sleep(60000);
						} catch (InterruptedException e) {
							// TODO Auto-generated catch block
							e.printStackTrace();
						}
					}
				};
				t.start();
				list.add(t);
				Thread.sleep(100);
			}
		}
	}
}

 

MMOTest.java

 

package dingchd;

public class MMOTest {
	static MMODemo mmodemo = new MMODemo();
	static DeadLockDemo tdemo = new DeadLockDemo();
	final static int DIRECTMMO = 0;
	final static int STACKMMO = 1;
	final static int HEAPMMO = 2;
	final static int PGMMO = 3;
	final static int THREADMMO = 4;
	final static int ALMMO = 5;
	final static int DEADLOCK = 6;

	public static void main(String args[]) throws Throwable {
		int option = -1;
		if (args.length == 0) {
			System.out.println("dingchd MMO TEST \r\n");
			System.out
					.println("0"
							+ "\t demo java.lang.OutOfMemoryError:Direct buffer memory");
			System.out.println("1" + "\t demo java.lang.StackOverflowError");
			System.out.println("2"
					+ "\t demo java.lang.OutOfMemoryError: Java heap space");
			System.out.println("3"
					+ "\t demo java.lang.OutOfMemoryError: PermGen space");
			System.out
					.println("4"
							+ "\t demo java.lang.OutOfMemoryError: unable to create new native thread");
			System.out
					.println("5"
							+ "\t demo java.lang.OutOfMemoryError: Requested array size exceeds VM limit");
			System.out.println("6" + "\t demo Thread DeadLock");
			return;

		}
		try {
			option = Integer.parseInt(args[0]);
		} catch (ArrayIndexOutOfBoundsException e) {
			System.out.println("please input valid num");
		}
		switch (option) {
		case DIRECTMMO: {
			mmodemo.displayDirect();
			break;
		}
		case STACKMMO: {
			mmodemo.displayStack();
			break;
		}
		case HEAPMMO: {
			mmodemo.displayHEAP();
			break;
		}
		case ALMMO: {
			mmodemo.displayArryaLimit();
			break;
		}
		case THREADMMO: {
			mmodemo.displayThreadLimit();
			break;
		}
		case PGMMO: {
			mmodemo.displayPermGen();
			break;
		}
		case DEADLOCK: {
			tdemo.display();
			break;
		}
		default:
			return;
		}
	}
}

 

测试：

 

直接内存溢出，比如GZip**Stream 没有close

 
 堆内存溢出

 

永久代内存溢出，持久不断加载类

 

不能创建新的线程

 

请求的数组长度太大

 

死锁

 

栈内存溢出，死循环递归调用