What is runtime polymorphism or dynamic method dispatch?

In Java, runtime polymorphism or dynamic method dispatch is a process in which a call to an overridden method is resolved at runtime rather than at compile-time. In this process, an overridden method is called through the reference variable of a superclass. The determination of the method to be called is based on the object being referred to by the reference variable. For example:

class Try    {
      void disp()   {}
}

class Test extends Try    {
      void disp()   {}
      public static void main(String args[]){
         Try t=new Try();
         Test t1=new Test();
         Try v;
         v=t1;
         v.disp(); // call to the disp() method from Test.
      }
}

Here, the Test version of the disp() method is called because the reference variable v of the type Try points to the Test object t1.

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