JPad FAQ

Updated 5/2/96


1. Do I need set the CLASSPATH environment variable in order to use JPad?

No, JPad uses the -classpath command line parameter to pass information to Java tools. However, if you are using other environments in addition to JPad, such as Netscape, you may need to set the CLASSPATH environment variable. You may also need to set the CLASSPATH if you are using the Run Applet command. See below.


2. I just installed JPad but the Compile menu is disabled. What's wrong?

If the Compile menu is disabled then that means that JPad cannot find javac.exe (the JDK compiler). To correct this you need to tell JPad where the java directory is located. First open JPad and then choose the Java Directory menu item from the Java menu. Then click browse and then open your java directory.

Note: your java directory is the directory with a bin and lib subdirectory. The bin directory should contain javac.exe along with all the other JDK tools.


3. I just tried to compile my first program but I get errors saying that one or more built-in java classes cannot be found? What's wrong?

If built-in java classes cannot be found it means that the classes.zip entry in the JPad Package Directories dialog does not identify a valid file. To correct this choose the menu item Packages Directories from the Java menu and double click on the entry classes.zip and edit. For example, if your Java Directory is D:\java then the entry for classes.zip file should be D:\java\lib\classes.zip. To check that this is working open the HelloWorld.java file in JPad Examples directory, compile and then run. You should not get any errors while compiling and should see the message "Hello World" when you run the HelloWorld application.


4. I'm trying to setup JPad but I can't find the classes.zip file in my JDK. Where is the classes.zip file?

Most likely you have a earlier version of JDK. To check, find the file javac.exe and check the date. If it was created before January 1996 then you do not have a current version of JDK. You need to download the latest version from Sun before you can use JPad.


5. I'm trying to build my own Java package, but the compiler cannot find my classes. What's wrong?

The first thing to check is to make sure that you have an entry in the JPad Package Directories dialog for the top folder containing your package. If you are defining subpackages then you also need to make sure that the folder structure matches the package structure. That's because JDK tools looks for a package by finding the corresponding folder starting with one of the entries in the JPad Package Directories dialog. For example, the package MyPackage.First should have a folder \MyPackage\First\ and the JPad Package Directories dialog should have an entry for the folder containing the folder MyPackage. For example, if MyPackage is a folder in the JPad folder then the entry would be C:\JPad


6. When I try to run an applet, JPad displays a command line dialog. What should I enter on the command line?

You should enter the URL of a html file that will test your applet. For example to run the example applet you would enter the following:

file:<path to your JPad directory>/JPad/Applet/Hello.html

For example, if JPad is installed in C:\JPad then the URL is file:C/JPad/Applet/Hello.html. Note that the directory separator should be a forward slash rather than the usual Windows backward slash.

If you have JPad version 1.0.6 or later you can just use the Browse button in the command line dialog to select your html file.


7. When I try to run an applet using JPad, I get errors saying that one or more classes cannot be found? What's wrong?

JDK's appletviewer is an exception to the other JDK tools in that it does not accept a classpath command line parameter. The simplest solution is to put all your applet classes in one folder together with your html test file(s) and to run the applet only when you have the source for one of your applets displayed in the front window. The other solution is to set the CLASSPATH environment variable to include the paths to your applet classes.


8. My applet runs just fine under JPad but it does not seem to run when I open my html page using a browser. What's wrong?

Check your browser documentation to see what you need to do to set it up to run Java applets.


9. Can I use JPad with JDK Beta 2?

JPad was built for JDK 1.0 and we recommend that you use JDK 1.0 or later. However if you must use JDK Beta 2 it appears, based on limited testing, that JPad is compatible.


10. I'm trying to compile my first class and JPad stops responding or I get a system error message. What wrong?

The most likely source of this problem is that you have something wrong with your JDK. Here are some things to check and do:

a) Is your distribution file OK? Sun recommends that you make sure that the size of the downloaded file is correct. See Sun's JDK site for more infomation

b) Do you have multiple JDK's installed? If so remove all but the latest.

c) If your distribution file looks OK try reinstalling JDK

d) If all else fails then get a new copy of JDK and try reinstalling.


11. How can I see or change the command line parameters that JPad passes to the JDK tools?

If you need to see or change the command line arguments that JPad passes to the Java tools hold down the shift key while choosing a Java menu item.

If you have JPad version 1.0.6 or later you can also add persistent custom options that will be added to your command line. See your Java manual pages for available options or enter in an invalid option and let the tool tell you the available options in the output panel.


12. Will JPad run on Windows NT 4.0?

JPad was developed for Windows 95 and NT 3.51. ModelWorks has done limited testing of JPad with Windows NT 4.0 Beta and did not find any major problems.


13. Will JPad run on Windows 3.1 or Windows NT 3.5?

No, JPad was developed for Windows 95 and NT 3.51. There are no plans to support these operating systems.


Copyright © 1996, ModelWorks Software. All rights reserved. JPad and JPad Pro are trademarks of ModelWorks Software. Java is a trademark of Sun Microsystems, Inc. Windows is a registered trademark of Microsoft Corporation.