Here is a snippet from my very own
java notes
* java 'implicit' up-casting rule is
The other type of casting is with refernce type, you don't need to do an explict cast with up-casting.
class A {}
class B extends A {}
A a1 = new B(); // no cast for up-casting
B b1 = new B();
A a2;
a2 = b1; // no casting required
B b2 = (B)a2; // need to cast when down-casting!
Hope this helps
[ March 09, 2002: Message edited by: Rajinder Yadav ]