Question

output of this program comes as “Inside Thread Inside Thread” , How this is happening?

class MyThread extends Thread 
{ 
    MyThread() {} 
    MyThread(Runnable r) {super(r); } 
    public void run() 
    { 
        System.out.print("Inside Thread ");
    } 
} 
class MyRunnable implements Runnable 
{ 
    public void run() 
    { 
        System.out.print(" Inside Runnable"); 
    } 
} 
class ThreadRunnableBoth 
{  
    public static void main(String[] args) 
    { 
        new MyThread().start();
        new MyThread(new MyRunnable()).start(); 
    } 
}

I can understand how first “Inside Thread” is printing but for second time print I am expecting to print “Inside Runnable” but it prints “Inside Thread” , how this is happening ?
Please explain …..thanks a lot

Answer 1

The run() method of java.lang.Thread simply calls target.run(), where target is the Runnable provided during construction. However, in MyThread, you’ve overridden this functionality; your version of run() ignores the target and prints “Inside Thread” instead.

One way to fix it is to run your Runnable with an instance of the base Thread class:

new Thread(new MyRunnable()).start();

Other possibilities would be not to override run(), or to call super.run() from your override.