Equivelant of "virtual function" from C++ in Java?

Question

I have a Java class which implements a network protocol. There are certain types of packets that my Java class will handle internally. Then again there are other types of packets my Java class needs to pass on to the Java MIDlet that is running this code (importing the package which implements the network protocol and using the class). In C++ I would make this all one class which has a virtual function OnReceive(). Then the C++ application using the class would provide their own implementation for OnReceive and every packet that my network code didn't know what to do with would be passed on to the new OnReceive. How can I do the same in Java? I would like to be able to create a new project, import my package which has the networking code in it. And code up a method that is specific to the application using the networking package. That way I only code one method to handle the packets that my networking code does not care about. I hope someone understands what I am getting at here, it is not so easy to explain.

Answer 1

Make your class abstract, define the pure virtual methods you want subclasseses to provide implementation for (using the abstract keyword in their definition) and you should be good.
public abstract class MyClass {
    public void concreteInitThing() {
        // your code here
    public abstract void specificImplementation();
public class ConcreteImplementationOfMyClass extends MyClass {
    public void specificImplementation() {
        // Your code here
}I hope that helped
Lee