Use of setPriority method of Thread Class in java

import java.io.*;

class A extends Thread
{ public void run()
   { System.out.println("Thread A started");
      for(int i=5;i>0;i--)
      { System.out.println(i);
       }
    }
}

class B extends Thread
{ public void run()
   { System.out.println("Thread B started");
      for(int i=5;i>0;i--)
      { System.out.println(i);
      }
    }
}

class C extends Thread
{ public void run()
   { System.out.println("Thread C started");
      for(int i=5;i>0;i--)
      { System.out.println(i); }
    }
}

class thread3
{ public static void main(String args[])
   { A thread_a=new A();
      B thread_b=new B();
      C thread_c=new C();

      thread_c.setPriority(Thread.MAX_PRIORITY);
      thread_b.setPriority(thread_a.MAX_PRIORITY);
      thread_a.setPriority(Thread.MIN_PRIORITY);

      System.out.println("Thread A");
      thread_a.start();

      System.out.println("Thread B");
      thread_b.start();

      System.out.println("Thread C");
      thread_c.start();
     
      System.out.println("End of Main Thread");
   }
}