polymorphic type means you have a superclass reference pointing to subclass object.
For example in case of overriding
class Animal
{
public void show()
{
System.out.println("Inside Animal");
}
}
class Horse extends Animal
{
public void show()
{
System.out.println("Inside Horse");
}
public static void main(
String args[])
{
Animal a = new Horse(); //Polymorphic Type
a.show(); //calls the horse version of the method
}
}