Finding the class to which an object belongs

Question

Let us have an object.
How can one find whether it is an
instance of an user defined class
or the one defined in any one of
java.* packages?
Thanks in advance.

Answer 1

Two ways:
1. You can use Java Reflection API (see Java tutorial).
2. Short and simple way:
Object x = new java.util.ArrayList();
if (x instanceof java.util.Collection) {
System.out.println("Bingo!");
} else {
System.out.println("Impossible!!!");
if (x instanceof Integer) {
System.out.println("Impossible!!!");
Basically, it will never print out "Impossible!!!"
I don't recomends using .getClass().getName().equals( some class name ), it is dirty. Keyword instanceof works for inheritance using class/ abstract class and interface.
rgds,
Alex