Is javax.swings.JFrame class a subclass of java.awt.Frame ?

**fatabass** · 12-20-2011, 07:51 PM

Quoting from the book: Java, Java, Java, Object-Oriented Problem Solving (3rd Edition)

"For example, the javax.swing.JFrame class, which represents a top-level window, is a subclass of java.awt.Frame."

Is this true ?

Link to the book is:
Amazon.com: Java, Java, Java, Object-Oriented Problem Solving (3rd Edition) (9780131474345): Ralph Morelli, Ralph Walde: Books

( I have not touched a single character on the text I have quoted. )

**Norm** · 12-20-2011, 08:00 PM

First and one of the best places to look:
Java Platform SE 6

**fatabass** · 12-20-2011, 08:01 PM

Well it looks like it is not, I just wanted to make sure since I am a beginner.

**DarrylBurke** · 12-20-2011, 08:07 PM

Too much trouble to look up the API, huh?

db

**KevinWorkman** · 12-20-2011, 08:08 PM

Originally Posted by fatabass

Well it looks like it is not, I just wanted to make sure since I am a beginner.

What makes you think it is not? From the API:

Java Code:

java.lang.Object
  extended by java.awt.Component
      extended by java.awt.Container
          extended by java.awt.Window
              extended by java.awt.Frame
                  extended by javax.swing.JFrame

**fatabass** · 12-20-2011, 08:09 PM

I am really not lazy.
I just cant be sure since that looks like a serious book.

So if you are here to judge, save your thoughts please.

All I require is simple Yes or No answer. I am a beginner, and I do not have anyone experienced around me to consult.

Thanks.

**Norm** · 12-20-2011, 08:11 PM

Did you bookmark the link to the API doc so you can find it easily for future questions like this one?

**KevinWorkman** · 12-20-2011, 08:11 PM

Nobody has judged you. Have you looked at the API? It's not a book, so since you're calling it one, the answer must be no. Looking at the API is a very important skill to learn, especially if you do not have other programmers to consult.

**fatabass** · 12-20-2011, 08:16 PM

I am not calling the API a book.

The book I am quoting from is a book.

And I was clearly mistaken that because they were different packages, I thought somehow it was wrong information.

I thought a class could only extend a class from the same package.

java.lang.Object
java.awt.Component
java.awt.Container
java.awt.Window
java.awt.Frame
javax.swing.JFrame

So I was confused in this last step where javax.swing.JFrame extends java.awt.Frame, because it is a different package.

Thanks.

**KevinWorkman** · 12-20-2011, 08:29 PM

Originally Posted by fatabass

I thought a class could only extend a class from the same package.

If that was the case, you couldn't get very far. How would anything outside of java.lang extend Object? How would you write your own classes that extend existing ones?

Lesson learned: test all of your assumptions! The best way to do this is to write small programs and consult the API.

**fatabass** · 12-20-2011, 08:33 PM

Yes I was confused with awt and swing, I remember reading something like AWT was old and Swing was something completely new and different.

I was clearly mistaken and confused. Sorry if the question was way too silly.

Anyway thanks, although it was a bit harsh, I learned that classes can extend classes from different packages.

Thanks again.