Making sure I have this dead lock concept without statics correct

[Rick Reumann]

Just so I have this clear..in the code below if the two objects had NOT been defined as static then a deadlock situation couldn't occur could it? Since each Thread object would have it's own Test object and thus it's own instances of obj1 and obj2 they would never get locked since m1() and m2() would always be waiting to be finsihed before the next one was called. (I would think the output could still not be determined, though, regardless of whether the Objects obj1 and obj2 were static or not).

public class Test extends Thread
{
 boolean flag = false;
 public Test(boolean f) { flag = f };
 static Object obj1 = new Object();
 static Object obj2 = new Object();
 public void m1()
 {
   synchronized(obj1) 
   {
     System.out.print("1 ");
     synchronized(obj2)
     {
       System.out.println("2");
     }
   }
 }
 public void m2()
 {
   synchronized(obj2) 
   {
     System.out.print("2 ");
     synchronized(obj1)
     {
       System.out.println("1");
     }
   }
 }

 public void run()
 {
  if(flag){ m1();  m2(); }
  else { m2();  m1(); }
 }
 public static void main(String[] args)
 {
   new Test(true).start();
   new Test(false).start();
 }
}

[Jose Botella]

I agree. If variables were non static, methods wouldn't be synchonized at all. And no deadlock would be possible. The same object must be used for properly synchronization.