Multithreaded printing

1 Two threads alternately print 1 To 100

static volatile int falg = 0;
    @Test
    public void test001(){
    

        Thread threadA = new Thread(new Runnable() {
    
            @Override
            public void run() {
    
                int i = -1;
                while(i < 100) {
    
                    if(KinglexCompanyExecutorApplicationTests.falg == 0){
    
                        i = i + 2;
                        System.out.println(i);
                        KinglexCompanyExecutorApplicationTests.falg = 1;
                    }
                }
            }
        });
        threadA.start();
        Thread threadB = new Thread(new Runnable() {
    
            @Override
            public void run() {
    
                int i = 0;
                while(i < 100){
    
                    if(KinglexCompanyExecutorApplicationTests.falg == 1){
    
                        i = i + 2;
                        System.out.println(i);
                        KinglexCompanyExecutorApplicationTests.falg = 0;
                    }
                }
            }
        });
        threadB.start();
    }

2 Three threads print alternately a、b、c

  static volatile int falg = 0;
    @Test
    public void test001(){
    

        Thread threadA = new Thread(new Runnable() {
    
            @Override
            public void run() {
    
                int i = 0;
                while(i < 100) {
    
                    if(KinglexCompanyExecutorApplicationTests.falg == 0){
    
                        i = i + 1;
                        System.out.println('a');
                        KinglexCompanyExecutorApplicationTests.falg = 1;
                    }
                }
            }
        });
        threadA.start();
        Thread threadB = new Thread(new Runnable() {
    
            @Override
            public void run() {
    
                int i = 0;
                while(i < 100){
    
                    if(KinglexCompanyExecutorApplicationTests.falg == 1){
    
                        i = i + 1;
                        System.out.println('b');
                        KinglexCompanyExecutorApplicationTests.falg = 2;
                    }
                }
            }
        });
        threadB.start();
        Thread threadC = new Thread(new Runnable() {
    
            @Override
            public void run() {
    
                int i = 0;
                while(i < 100){
    
                    if(KinglexCompanyExecutorApplicationTests.falg == 2){
    
                        i = i + 1;
                        System.out.println('c');
                        KinglexCompanyExecutorApplicationTests.falg = 0;
                    }
                }
            }
        });
        threadC.start();
    }