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Thread: Question about threading.

  1. #1
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    Default Question about threading.

    From what I can gather, the following code is supposed to execute each thread in a random order and different each time. For me the output is as if I'm not threading at all. First prints 5 times, second prints 5 times, third prints 5 times. I can't see anything wrong with the code.

    // second program to demonstrate creation of thread by extenting thread class
     
    class First extends Thread{      // FirstThread extended from java.lang.Thread
     
       public void run(){            // run method of class
     
          for(int i =1 ; i <=5; i++){   // when run, cycle 5 times
     
             System.out.println("First Thread is running.");
          }
       }
    }
     
    class Second extends Thread{        // second thread
     
       public void run(){               // run method of class
     
          for(int j = 1; j <=5; j++){      // run 5 times
     
             System.out.println("Second Thread is running.");
          }
       }
    }
     
    class Third extends Thread{         // third thread
     
       public void run(){               // run method of class
     
          for(int k = 1; k<=5; k++){    // run 5 times
     
             System.out.println("Third Thread is running.");
          }
       }
    }
     
    public class ThreadCreateExtend2{
     
       public static void main(String args[]){
     
          First f1 = new First();          // create object of First named "f1"
          f1.start();                      // call start() method inherited from thread class
          Second s1 = new Second();
          s1.start();
          Third t1 = new Third();
          t1.start();
       }
    }

  2. #2
    Super Moderator Norm's Avatar
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    Default Re: Question about threading.

    Modern computers are very fast. When the code calls the first start() the thread is started and executes the loop before the code can call the second start.
    To cause the printed output to be interleaved, add a call to sleep to slow down the loop and allow the next start to be executed before the current loop ends.

    Also to see what is happening, print out the value of System.currentTimeMillis() with each print statement.
    If you don't understand my answer, don't ignore it, ask a question.

  3. The Following User Says Thank You to Norm For This Useful Post:

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