Can a subclass type variable refer to a superclass object?

Question

In Java's class hierarchy, can an object be initialized in such a manner?

subclass object = new superclass();

This assumes that both the subclass and superclass have proper constructors, can compile, etc. Is this type of object construction possible?

score 0 · Accepted Answer · answered Mar 19 '17 at 17:34

No. Only the other way around. When you have an object of a class you can refer to it by a reference of the same class or a parent class and not the reverse. This is probably not related to just Java. Otherwise it wouldn't make sense. Suppose you have

class SuperClass {
    public void method1() {};
}

class SubClass {
    public void method2() {};
}

If you do

  SubClass object = new SuperClass();

and then

  object.method2();

then theoretically it should compile, because the reference is of type SubClass, but the object is of type SuperClass so it won't have such a method.

Can a subclass type variable refer to a superclass object?

1 Answers1