Hi,
Overloading means to have multiple method with the same name (but different signatures) in one class. For eg:
public class Calc {
int sum(int x, int y) {}
float sum (float x, float y) {}
}
In this case the method sum has been overloaded. Note that the signatures are different.
Overriding is re-implementing a method (which is already implemented in a superclass) in a subclass. For eg:
public class Superclass {
public void printSomething() {
System.out.println("This is the superclass");
}
}
public class Subclass extends Superclass {
public void printSomething() {
System.out.println("This is the subclass");
}
}
As for Polymorphism, a one line definition would not really suffice for the concept. I suggest reading some good book. There is an excellent free digital book on Java available from
www.bruceeckel.com , called Thinking in Java.
Hope that helps
Parag