1、執行緒不共享資料
對同一資源，各個執行緒各自執行一遍，程式碼如下:

package com.zzm.th01;

/**
 * 執行緒不共享資料
 * Created by ming on 2017/6/15.
 */
public class th04 extends Thread{
    //記錄資源總數
    private int count = 4;
    @Override
   public void run() {
        super.run();
        count--;
        System.out.println(Thread.currentThread().getName()+"執行->"
 
+count);
    }

    public static void main(String[] args) {
        th04 th = new th04();
        th04 th1 = new th04();
        th04 th2 = new th04();
        th.start();
        th1.start();
        th2.start();
    }
}

2、執行緒資料共享
這種情況會有非執行緒安全問題。需要加synchronized。程式碼如下：

package com.zzm.th01;

/**
 * Created by ming on 2017/6/15.
 */
 

public class th05 extends Thread {
    int count = 7;
    @Override
  synchronized   public void run() {
        super.run();
        count--;
        System.out.println(Thread.currentThread().getName()+"執行->"+count);
    }

    public static void main(String[] args) {
        th05 th = new th05();
        Thread th1 = new
 
 Thread(th,"執行緒1");
        Thread th2 = new Thread(th,"執行緒2");
        Thread th3 = new Thread(th,"執行緒3");

        th1.start();
        th2.start();
        th3.start();
    }
}