Question

I want to run my applet on web application, but i got some error which i mentioned below please help me to get out of this problem

Java Plug-in 1.7.0
Using JRE version 1.7.0-ea-b116 Java HotSpot(TM) Client VM
User home directory = C:\Users\HONEY
----------------------------------------------------
c:   clear console window
f:   finalize objects on finalization queue
g:   garbage collect
h:   display this help message
l:   dump classloader list
m:   print memory usage
o:   trigger logging
q:   hide console
r:   reload policy configuration
s:   dump system and deployment properties
t:   dump thread list
v:   dump thread stack
x:   clear classloader cache
0-5: set trace level to <n>
----------------------------------------------------


java.lang.RuntimeException: java.lang.NoClassDefFoundError: mp3$1
 at sun.plugin2.applet.Plugin2Manager.createApplet(Unknown Source)
 at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
 at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NoClassDefFoundError: mp3$1
 at mp3.<init>(mp3.java:93)
 at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
 at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
 at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
 at java.lang.reflect.Constructor.newInstance(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.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: mp3$1
 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)
 ... 16 more
Caused by: java.io.IOException: open HTTP connection failed:http://viscous10.webng.com/mp3/mp3$1.class
 at sun.plugin2.applet.Applet2ClassLoader.getBytes(Unknown Source)
 at sun.plugin2.applet.Applet2ClassLoader.access$000(Unknown Source)
 at sun.plugin2.applet.Applet2ClassLoader$1.run(Unknown Source)
 at java.security.AccessController.doPrivileged(Native Method)
 ... 21 more
Exception: java.lang.RuntimeException: java.lang.NoClassDefFoundError: mp3$1

but it happens only if i run applet with events
and in simple applet i never occurred

Answer 1

This error means the Java runtime cannot find the .class file for an anonymous inner class of your mp3 class. Anonymous inner classes are named OuterClass$1, OuterClass$2, OuterClass$3 and so on. An example of the definition of an anonymous inner class:

  button1.addActionListener(
     new java.awt.event.ActionListener()
     {
        public void actionPerformed(java.awt.event.ActionEvent e)
        {
           // do something
        }
     }
  );

As it seems you are using inner classes, be aware that your mp3.java source file creates various .class files and make sure all of these .class files are available for the runtime environment (via copying, or adding them in a .jar file, etc).