class A{
	//有無註釋程式碼都沒有影響，輸出就是aaa BBB
	//static A a=new A();
	static{
		System.out.println("aaa");
	}
	public void B() {
		System.out.println("BBB");
	}
}
public class statictest {
	public static void main(String[] args) {
		A a1=new A();
		a1.B();
		A a2=new A();
	}
	
}

class test1 extends Thread{
	public void run(){
		System.out.println("pong");
	}
}
public class pongping {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		test1 t=new test1();
		//用t.run()pong ping
		// t.run();
		// System.out.println("ping");
		
		//用t.start()ping pong和pong ping都有可能
		t.start();
		System.out.println("ping");
	}

}