[Java] Call a run() directly instead start()

Call a run() directly instead start()

- Each thread starts in a separate call stack, like this

- Invoking the run() from main thread, the run() method goes onto the current call stack 

1. Problem

public class directRn extends Thread{ public void run(){ for(int i = 0; i<5;i++){ try{ Thread.sleep(500); }catch(InterruptedException e){ System.out.println(e); } System.out.println(i); } } public static void main(String[]args){ directRn t1 = new directRn(); directRn t2 = new directRn(); t1.run(); t2.run(); } }

- There is no context-switching 

- t1 and t2 will be treated as normal object not thread object