Difference in initialazing objects in java

Question

Let's say I have an abstract class A and a class called B extending it. What's the difference between initializing like this:

A objectname=new B();

and this

B objectname=new B();  

Answer 1

In both cases you'd be creating an instance of B. The only difference is where you assign this instance. In the first snippet, objectname is of type A, so you won't be able to use B's methods that aren't in A unless you explicitly cast it to B.