请编写一个多线程程序，实现两个线程，其中一个线程完成对某个对象的int成员变量的增加操作，即每次加1，另一个线程完成对该对象的成员变量的减操作，即每次减1，同时要保证该变量的值不会小于0，不会大于1，该变量的初始值为0.

package crease;

public class Sample {
	int number = 0;
	
	public synchronized void add(){
		while(number > 0){
			try {
				wait();
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
		number ++;
		System.out.print(number);
		notify();
	}
	
	public synchronized void jian(){
		while(number == 0){
			try {
				wait();
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
		number--;
		System.out.print(number);
		notify();
	}
}

package crease;

public class TestSample {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		Sample sample = new Sample();
		new AddThread(sample).start();
		new JianThread(sample).start();
	}

}

class AddThread extends Thread{
	private Sample sample;
	public AddThread(Sample sample){
		this.sample = sample;
	}
	
	public void run(){
		for(int i=0;i<10;i++){
			try {
				Thread.sleep(1000);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			sample.add();
		}
	}
}

class JianThread extends Thread{
	private Sample sample;
	public JianThread(Sample sample){
		this.sample = sample;
	}
	
	public void run(){
		for(int i=0;i<10;i++){
			try {
				Thread.sleep(1000);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			sample.jian();
		}
	}
}