Getting to know concurrency problems

Initial understanding of concurrency problem

//  Multiple threads operate on the same object at the same time 
//  An example of buying a train ticket 

//  Find the problem ： When multiple threads operate on the same resource , Thread unsafe , Data disorder 
public class TestThread4 implements Runnable {
    
    private int ticketNum = 10;
    @Override
    public void run() {
    
        while (true){
    
            if (ticketNum <= 0){
    
                break;
            }
            //  Analog delay 
            try {
    
                Thread.sleep(200);
            } catch (InterruptedException e) {
    
                e.printStackTrace();
            }
            System.out.println(Thread.currentThread().getName() + "---> Got the number " + ticketNum-- + " ticket ");
        }
    }

    public static void main(String[] args) {
    
        TestThread4 testThread4 = new TestThread4();

        new Thread(testThread4," Xiao Ming ").start();
        new Thread(testThread4," Xiaohong ").start();
        new Thread(testThread4," Cattle ").start();
    }
}

give the result as follows

 Cattle ---> Got the number 9 ticket 
 Xiao Ming ---> Got the number 8 ticket 
 Xiaohong ---> Got the number 10 ticket 
 Xiaohong ---> Got the number 7 ticket 
 Xiao Ming ---> Got the number 5 ticket 
 Cattle ---> Got the number 6 ticket 
 Cattle ---> Got the number 4 ticket 
 Xiao Ming ---> Got the number 4 ticket 
 Xiaohong ---> Got the number 4 ticket 
 Cattle ---> Got the number 3 ticket 
 Xiao Ming ---> Got the number 3 ticket 
 Xiaohong ---> Got the number 2 ticket 
 Cattle ---> Got the number 1 ticket 
 Xiaohong ---> Got the number 1 ticket 
 Xiao Ming ---> Got the number 1 ticket