I have a question about using java applet on google app engine. I created 2 classes called InteractiveGraphView1 and SimpleApplet. Using an object of InteractiveGraphView1 inside SimpleApplet. Anyway, I’m using some external jars for these 2 classes. I created a jar for my project called “GraphApplet”. Then I put this jar into WEB-INF/lib and also I add it into gae project as external jar. To be sure I also added external jars that I used in GraphApplet class into my gae project. I deployed the gae project and when I tried to run applet it gives me this error:
load: class SimpleApplet.class not found.
java.lang.ClassNotFoundException: SimpleApplet.class
at sun.plugin2.applet.Applet2ClassLoader.findClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass0(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadCode(Unknown Source)
at sun.plugin2.applet.Plugin2Manager.createApplet(Unknown Source)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Exception: java.lang.ClassNotFoundException: SimpleApplet.class
java.lang.RuntimeException: java.lang.NoClassDefFoundError: edu/uci/ics/jung/algorithms/layout/Layout
at sun.plugin2.applet.Plugin2Manager.createApplet(Unknown Source)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NoClassDefFoundError: edu/uci/ics/jung/algorithms/layout/Layout
at java.lang.Class.getDeclaredConstructors0(Native Method)
at java.lang.Class.privateGetDeclaredConstructors(Unknown Source)
at java.lang.Class.getConstructor0(Unknown Source)
at java.lang.Class.newInstance0(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at sun.plugin2.applet.Plugin2Manager$12.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$400(Unknown Source)
at java.awt.EventQueue$2.run(Unknown Source)
at java.awt.EventQueue$2.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Caused by: java.lang.ClassNotFoundException: edu.uci.ics.jung.algorithms.layout.Layout
at sun.plugin2.applet.Applet2ClassLoader.findClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass0(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 20 more
Exception: java.lang.RuntimeException: java.lang.NoClassDefFoundError: edu/uci/ics/jung/algorithms/layout/Layout
What should I do?
P.S. I forgot to tell that I’m using JUNG library in my GraphApplet project. I also added this into google app engine project
Adding into HMTL
<html>
Hello App Engine
This is my page<br>
Below you see an applet<br>
<br>
<Applet Code="SimpleApplet.java" archive="graphic.jar" width=200 Height=200>
</Applet>
Applet is just a jar file that is downloaded by browser and executed on client side as applet.
It has nothing to do with server code. From the point of server it’s just a static file. So you should not pout it inside
WEB-INF/lib, where server libs reside. Just put it next to your html files.For an applet referring to other jars see: How do I build an applet which needs an external jar, using ant?