Most of these questions can be answered by a careful reading of the book, but I get asked them anyway. Before writing to me, please check to see if your question is already answered here.

I used Notepad to type in a Java applet straight from the book. When I try to run the applet, however, I get the error "class HelloWorld cannot be found".

Notepad is not an IDE (Integrated Development Environment). You'll need a program that can take a .java file and create a .class file. IDEs are covered on page 6, and tips on the different IDEs are given in Appendix A. The online version of Appendix A also includes links to buy all the software online.

I got an IDE, but I can't figure out how to use it to create .class files.

You'll have to look at the documentation that came with the IDE. Unfortunately, I can't afford to buy every IDE on the market, much less all the hardware that's needed to run every possible variation.

I uploaded the .class file to the same directory as my HTML file, but I get the error "class HelloWorld cannot be found". I know it's there; what's the problem?

Take a look at the CODEBASE attribute of your APPLET tag. That shows the directory where the server is expecting to find the applet (page 20).

When I try to compile some of the applets, I get a deprecation warning--what does that mean?

Java has gone through several different versions (as discussed on page 7). Your IDE is letting you know that it can handle a version of Java greater than 1.0. Or, in Java jargon, it's telling you that version 1.0 has been "deprecated," i.e., there's a newer version out, which your IDE thinks you should be using.

However, the situation given in page 7 still hasn't changed in 2000. Just using the Mac as an example: Netscape 4.x doesn't support Java 1.1 fully. IE 5 (with the current version of MRJ) only supports Java 1.1, not 1.2 or 2.0. So, if you want to be cross-platform and cross-browser, you're stuck with using Java 1.0 for now.

So what to do about the warning? Basically, don't worry about it. If you want to use an older version of Java than it wants you to, well, you're a person who knows more than your software. Some IDE's let you turn this warning message off; if you can, I recommend it.

Do you have a .zip file that I can download?

Yes, finally! You can find a link to it on the applets page, or you can download it directly from here.

I have a Java question that has nothing to do with your book. Are you available for consulting?

Between teaching and working on my next book, I'm not taking on any consulting projects at this time. Thanks for asking, though.

Ask me a question about the book!