If your Java applet does not run Prashanth Sanagavarapu

Problems with applets? Many students face problems while running Applets from AFS. some of the common Problems are… Applet Not initiated Applet loading Failed Source not found.

Problems with applet? (cont..) (Imaginary) messages from my mail box : Dear Prof, My applet works on my laptop but does not work on web. Please grade my work through screen shot or I will show it class on my laptop. Prof Replies : Dear student, This course is “Java and the Web” not “Java on Your Laptop.”

Failed Loading The most common problem you see…. This means your applet failed!

Files in Same Folder? Did you keep the class files and html document containing the class file in same folder? If you don’t have them in the same folder, it is harder to write the code to get them to load. (It can be done.) Ex : Use single folder to store all related files as above

Backslash in URL One of the most common Error Messages is Loading Applet Failed !! Do you have a backslash \ instead of a / in your URL? ( Put mouse pointer over link, look at bottom of screen.) correct form (bottom of browser): \ java.htm will work in IE on Windows, but not on other browsers, and will not work on AFS or any Unix version.

NetBeans or Eclipse Setup When you see your applet running on Laptop and it doesn’t run on the Web, especially if you are using Eclipse or Netbeans, declare all the classes in the default package. Do not use a package name. Runningapplet will work on web This HelloWorld Applet is harder to transfer to Web

Small changes in file names Another common mistake is to use different case for the class name in your html code. Ex: If HelloWorld.Class is the class file and you misprint it as Helloworld.class in html code then applet can not find the source and fails to run. Check the “W” HelloWorld, Helloworld, and helloworld are three different names to Unix and most browsers, although they are the same name to Windows and Internet Exploder.

Using awt and Swing components There is a special version of applet to use when you are using abstract windows toolkit and Swing components—the JApplet class. JApplet is volatile. The current version (JDK 1.5) has limited serializability and will be incompatibly changed in future versions. But it is still the best version to use with a LayoutManager. See the tutorial on “How to Make Applets” in the Java Tutorial and the documentation for the javax.swing interface RootPaneContainer.

Key resource: Web Board If there are any other problems other than these, Please post them on Web Board. This will help you and others. Web Board’s Tech support can be life saver at the last minute before exams & project due dates.

Source of information My personal experience from doing Java homework in CIS 602—Prashanth Sanagavarapu.