Help.....Thread

[Aru Ven]

Hi All,
Can anyone explain me the output of the program.....

class TestClass extends Thread {
     static Object lock1 = new Object( );
     static Object lock2 = new Object( );
     static volatile int i1, i2, j1, j2, k1, k2;
     public void run( ) {             
         while (true) {
           workWithLocks( );
           workWithoutLocks( );     
         } 
     }
    void workWithLocks( ) {
       synchronized(lock1) { i1++ ;  i2++; }
       synchronized(lock2) { k1++ ; k2++ ; }
       j1++ ;    j2++ ;
     }
     void workWithoutLocks( ) {
           if (i1 != i2) System.out.println("i");
           if (j1 != j2) System.out.println("j"); 
           if (k1 != k2) System.out.println("k");
     }
      public static void main(String args[ ] ) {
           new TestClass( ).start( );
           new TestClass( ).start( );
      }
}

Thanks in advance.
Aruna

[Vladimir Kositsky]

hi!
both treads increment i,k, and j in each of eternal loop invocation and return equal values.
so letters printed if workWithoutLocks( ) executed between first and second variables increment , and it is possible without any legimitacy.
see example 9.6 Mugal and Pasmussen
cheers

[shalini Rajan]

Hi Aruna,
I can't predict the result.Itz displaying infinite 'j' thatz right but some time it displays i & k also.I don't know why?.Lets wait for others to answer.
Shalini

[Praveen Zala]

Hi Aru,
The code that u have posted started printing k,j.........and so
on ...it prints the same witout stopping ...infinitely....
Wonder why it does that !
Prav

[Nasir Khan]

I changed the line if (j1 != j2) System.out.println("j");
with if (j1 != j2) System.out.println(j1+"j"+j2);
and found that the condition j1 != j2 is true after going through several loops ..
It seems that after sometime one thread lags behind the other one