线程安全不安全的辅助理解，可以拿这个例子自己去运行看看

public class Test {
	//LinkedList线程不安全
	//List<Integer>list=new LinkedList<Integer>();
	//Vector线程安全
	List<Integer> list=new Vector<Integer>();
	
	public static void main(String[] args)  {
		Test test=new Test();
		
		ThreadA tA = test.new ThreadA();
		ThreadB tB = test.new ThreadB();
		
		tA.start();
		tB.start();
		try{
			tA.join();
			tB.join();
		}catch(InterruptedException e){
			e.printStackTrace();
		}
		System.out.println("list size:"+test.list.size());
		
	}
	class ThreadA extends Thread{
		@Override
		public void run(){
			super.run();
			for(int i=0;i<100;i++){
				list.add(i);
			}
		}
	}
	class ThreadB extends Thread{
		@Override
		public void run(){
			super.run();
			for(int i=0;i<100;i++){
				list.add(i);
			}
		}
	}
}