Solved

Question on event listeners ..

Posted on 2002-04-19
1
206 Views
Last Modified: 2010-03-31
Hi,

I'm learning Java and have understood that you have to 'implement' any listeners in the class definition to be able to use them.

ie public class ChangeTitle extends JFrame implements ActionListener

I have just entered and run a book example that implements the ActionListener event handler, but not only does the class use the 'addActionListener' method in the class constructor, but in the main() definition for the class it ALSO uses 'addWindowListener' ?????

How can this class use the WindowListener if hasn't 'implemented' it in the class definition.

ie shouldn't the class definition should be ;

public class ChangeTitle extends JFrame implements ActionListener, WindowListener

instead of

public class ChangeTitle extends JFrame implements ActionListener

The small program compiles and runs okay.
0
Comment
Question by:Cacker
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
1 Comment
 
LVL 15

Accepted Solution

by:
ozymandias earned 25 total points
ID: 6953941
JFrame is a subclass of java.awt.window which has a method called addWindowListener(). The method you see in the JFrame is calling that method. It is a feature of inheritance.
0

Featured Post

Free Tool: Port Scanner

Check which ports are open to the outside world. Helps make sure that your firewall rules are working as intended.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Go is an acronym of golang, is a programming language developed Google in 2007. Go is a new language that is mostly in the C family, with significant input from Pascal/Modula/Oberon family. Hence Go arisen as low-level language with fast compilation…
In this post we will learn how to connect and configure Android Device (Smartphone etc.) with Android Studio. After that we will run a simple Hello World Program.
Viewers will learn about the regular for loop in Java and how to use it. Definition: Break the for loop down into 3 parts: Syntax when using for loops: Example using a for loop:
The viewer will learn how to implement Singleton Design Pattern in Java.
Suggested Courses

739 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question