Why I cannot access Child Object method with Parent Type

Question

object a2 is of type A but references an object of class C. So, a2 should be able to access m3(). But, why is it not happening? If m3() method had been defined in class A, t

Answer 1

Compiler checks reference of object which is invoking a method... In your case A a2=... is what compiler can see, and it finds that there is no m3() method defined in A class. Hence code will not compile.

Note that, While invoking method at runtime, JVM refers the object referenced by the Reference. In your case Reference of class A is referring Object of class C.

Read more at : Polymorphism in Java