I'm using Eclipse for several projects on Leopard OSX. I've installed several versions (Classic, PDT, etc). When I install a new plug-in using the Help > Install New Software functionality and I restart it, I always get the same error and I cannot anymore use it:

!ENTRY org.eclipse.equinox.launcher 4 0 2010-04-20 17:32:42.540
!MESSAGE Exception launching the Eclipse Platform:
java.lang.ClassNotFoundException: org.eclipse.core.runtime.adaptor.EclipseStarter
    at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:317)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
    at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:556)
    at org.eclipse.equinox.launcher.Main.basicRun(Main.java:514)
    at org.eclipse.equinox.launcher.Main.run(Main.java:1311)

What is causing the error? How can I get these plugins to work?


  • If you're a Java developer then you should know what that means. If you're not a Java developer then you shouldn't be using Eclipse. – Hasaan Chop Apr 22 '10 at 7:24
  • it's like something's wrong with plugin.xml dev.eclipse.org/newslists/news.eclipse.platform.rcp/… – Ye Lin Aung Apr 22 '10 at 7:38
  • 1
    @Hasaan: Either you are not a Java developer, have never used eclipse or have completely bizarre ideas of what constitutes common knowledge. This is an internal problem of eclipse and certainly nothing that every Java developer can be expected to know. – Michael Borgwardt Apr 22 '10 at 8:56

A few things to try:

  • Start eclipse with the -clean option (could fix corrupted workspace settings)
  • Start with the -debug option and look at workspace/.metadata/.log to see whether it gives you more information
  • Use the -vm option to make eclipse use a different JVM (I've seen a German forum post where someone had this problem after a MacOS update set the system default to an older JVM).

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