JPad Pro FAQ

JavaScript


1. I just ran the Syntax Check tool on my page and it did not find any errors, yet when I try to open the page using a browser it gives me an error. What wrong?

The Syntax Check tool only checks for syntax errors and invalid object model references related to JavaScript - it does not check many HTML errors or for most runtime errors.


2. How can I debug my page?

First you should run the Syntax Check tool and correct the problems found. Your next steps will depend upon the runtime problems remaining in the page. It's difficult to be specific, but here are some techniques that can help you to debug your page:


Java/JDK


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

No, JPad Pro uses the -classpath command line parameter to pass information to Java tools. However, if you are using other environments in addition to JPad Pro, 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 Pro but the Compile menu is disabled. What's wrong?

If the Compile menu is disabled then that means that JPad Pro cannot find javac.exe (the JDK compiler). To correct this you need to tell JPad Pro where the java directory is located. First open JPad Pro, then open a .java file and then choose the Configure menu item from the Tools 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 Classpaths dialog does not exist or does identify a valid file. To correct this choose the Configure menu item from the Tool menu, click on the Classpaths button, and then add an entry classes.zip. 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 Pro 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 Pro 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 Pro to compile and run Java programs.


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 Pro Classpaths 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 Classpaths dialog. For example, the package MyPackage.First should have a folder \MyPackage\First\ and the Classpaths dialog should have an entry for the folder containing the folder MyPackage. For example, if MyPackage is a folder in the JPad Pro folder then the entry would be C:\JPad Pro


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

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

<path to your JPad Pro directory>\JPad Pro\Applet\Hello.html


7. When I try to run an applet using JPad Pro, 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 Pro 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 Pro with JDK Beta 2?

JPad Pro was built for JDK 1.0 and we recommend that you use JDK 1.0 or later (the current release is 1.0.2). However if you must use JDK Beta 2 it appears, based on limited testing, that JPad Pro is compatible.


10. I'm trying to compile my first class and JPad Pro 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 JDK 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) If your distribution file looks OK try reinstalling JDK Also check to make sure that you can open the classes.zip file. If this does not work then contact ModelWorks


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

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

You can also configure your command line options by using the Configure dialog.


12. Will JPad Pro run on Windows NT 4.0?

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


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

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


14. Where can I find a Java help file?

You can find the "Dippy Bird Java Documentation" at http://www.dippybird.com


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.