Three ways to create threads

from https://blog.csdn.net/weixin_49920327/article/details/123561378

1. Inherit Thread class

**1） Create a class , Inherit Thread And rewrite run Method
2） Create objects perform start Method **

// Create thread mode one ： Inherit Thread class , rewrite run() Method , call start() Open thread 
public class TestThread1 extends Thread{
    

    @Override
    public void run() {
    
        //run() Method thread body 
        for (int i = 0; i < 20; i++) {
    
            System.out.println(" I'm looking at the code ——————" +i);
        }
    }

    public static void main(String[] args) {
    
        //main() Threads , The main thread 
        // Create an object 
        TestThread1 testThread1 = new TestThread1();
        // call start() Method 
        testThread1.start();

        for (int i = 0; i < 20; i++) {
    
            System.out.println(" I'm learning multithreading " + i);
        }
    }
}

2. Realization Runnable Interface

1） Create a class Realization Runnable Interface and Implementation run Method
2） Create a This kind object
3） Create a Thread object , The input parameters of the construction method are This kind object
4）Thread object perform start Method

// Create thread mode 2: Realization runnable Interface , rewrite run Method , The execution thread drops runnable Interface implementation class , call start() Method 
public class TestThread3 implements Runnable{
    
    @Override
    public void run() {
    
        for (int i = 0; i < 20; i++) {
    
            System.out.println(" Threads " + i);
        }
    }

    public static void main(String[] args) {
    
        // establish runnable Implementation class object of interface 
        TestThread3 testThread3 = new TestThread3();
        // Creating thread objects , Open our thread through thread object , agent 
// Thread thread = new Thread(testThread3);
// thread.start();
        new Thread(testThread3).start();
        for (int i = 0; i < 20; i++) {
    
            System.out.println(" Study " +i);
        }
    }
}

3. Realization Callable Interface （ understand ）

1） Create a class implementation Callable Interface , rewrite call Method
2) Create target object
3) Create an execution service
4） Submit for execution
5） Get the return result
6） Close execution service

// Implement a class , rewrite call() Method ,
public class TestCallable implements Callable<Boolean> {
    
    @Override
    public Boolean call() {
    
        for (int i = 0; i < 20; i++) {
    
            System.out.println(Thread.currentThread().getName() + " at work -----" + i);
        }
        return Boolean.TRUE;
    }
    public static void main(String[] args) throws ExecutionException, InterruptedException {
    
        TestCallable t1 = new TestCallable();
        TestCallable t2 = new TestCallable();
        TestCallable t3 = new TestCallable();
        
        // Create execution service 
        ExecutorService executorService = Executors.newFixedThreadPool(3);
        
        // Submit for execution 
        Future<Boolean> result1 = executorService.submit(t1);
        Future<Boolean> result2 = executorService.submit(t2);
        Future<Boolean> result3 = executorService.submit(t3);
        
        // To get the results 
        Boolean r1 = result1.get();
        Boolean r2 = result2.get();
        Boolean r3 = result3.get();
        
        // Close the service 
        executorService.shutdownNow();
    }
}