无法修复Java中的NoClassDefFound错误

Question

I build project in eclipse - swing applet and now I'm trying to run it in a browser.

I have 3 packages, let's say they are called: "pkgApplet", "pkgFirst", "pkgSecond" with .class files. In pkgApplet I have class "main" with method main() . No matter what I do, I can't run this applet in browser. Currently my html code looks like this

<applet code="bin/pkgApplet/main" height="1000" width="1000"/>

Browser gives this error every time no matter how I modify applet tag:

NoClassDefFoundError with message bin/pkgApplet/main(wrong name: applet/main)

I tried using codebase attribute, packing applet into .jar file and using archive attribute, but nothing seems to work. Do you have any idea what am I doing wrong?

Answer 1

Your applet format should be:

<applet codebase="bin" code="pkgApplet.main" height="1000" width="1000"></applet>

bin is the default target directory (for Eclipse) so will require the codebase attribute as shown above. For this to work, your HTML file needs to be located in your project directory.

Note classes in Java start with uppercase, while package names are lowercase. Also its helpful to name classes describing what they do. You could have instead:

<applet codebase="bin" code="pkgapplet.MyMainApplet" height="1000" width="1000"></applet>

Do you realize that nothing in main will be called by your applet client? Any startup functionality should be placed in the init method.