死鎖簡單實例

線程A

public class ThreadA implements Runnable {
	private A a;
	private B b;

	public ThreadA(A a, B b) {
		super();
		this.a = a;
		this.b = b;
	}

	@Override
	public void run() {
		System.out.println("A線程啓動");
		synchronized (a) {
			System.out.println("A線程持有a對象");
			try {
				Thread.sleep(20);
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			synchronized (b) {
				System.out.println("A線程持有b對象");
			}
		}
		System.out.println("A線程結束");
	}

}

線程B

public class ThreadB extends Thread {
	private A a;
	private B b;

	public ThreadB(A a, B b) {
		super();
		this.a = a;
		this.b = b;
	}

	@Override
	public void run() {
		System.out.println("B線程啓動");
		synchronized (b) {
			System.out.println("B線程持有b對象");
			try {
				Thread.sleep(20);
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			synchronized (a) {
				System.out.println("B線程持有a對象");
			}
		}
		System.out.println("B線程結束");
	}

}

對象A,B

public class A {

}


public class B {

}

測試

public class Test {

	public static void main(String[] args) {
		A a = new A();
		B b = new B();
		ThreadA ta = new ThreadA(a, b);
		new Thread(ta).start();
		
		ThreadB tb = new ThreadB(a,b);
		tb.start();
	}

}