Eclipse Kepler startup error "NoClassDefFoundError: org/eclipse/swt/widgets/Display"

Question

I am using Eclipse Kepler 64-bit and Sun JDK 1.7.0_25 64-bit on Ubuntu 64-bit. Eclipse worked when I had JDK 1.6 but stopped working after upgrading to JDK 1.7 (using webupd8.org's method and the popular askubuntu solution) and now at start-up it tells me there was an error and to check the configuration/xxx.log files.

This is the beginning of the contents of each log file it creates at start-up:

!SESSION 2013-07-08 15:38:11.495 -----------------------------------------------
eclipse.buildId=4.3.0.I20130605-2000
java.version=1.7.0_25
java.vendor=Oracle Corporation
BootLoader constants: OS=linux, ARCH=x86_64, WS=gtk, NL=en_US
Command-line arguments:  -os linux -ws gtk -arch x86_64

!ENTRY org.eclipse.equinox.ds 4 0 2013-07-08 15:38:12.212
!MESSAGE [SCR] Exception while activating instance org.eclipse.e4.ui.css.swt.internal.theme.ThemeEngineManager@b1320f9 of component org.eclipse.e4.ui.css.swt.theme  
!STACK 0
java.lang.NoClassDefFoundError: org/eclipse/swt/widgets/Display
        at java.lang.Class.getDeclaredMethods0(Native Method)
        at java.lang.Class.privateGetDeclaredMethods(Class.java:2521)
        at java.lang.Class.getDeclaredMethods(Class.java:1845)
        at org.eclipse.equinox.internal.ds.model.ServiceComponent.getMethod(ServiceComponent.java:126)
        at org.eclipse.equinox.internal.ds.model.ServiceComponent.activate(ServiceComponent.java:213)
        at org.eclipse.equinox.internal.ds.model.ServiceComponentProp.activate(ServiceComponentProp.java:146)
        at org.eclipse.equinox.internal.ds.model.ServiceComponentProp.build(ServiceComponentProp.java:345)
        at org.eclipse.equinox.internal.ds.InstanceProcess.buildComponent(InstanceProcess.java:620)
        at org.eclipse.equinox.internal.ds.InstanceProcess.buildComponents(InstanceProcess.java:197)

I have cleaned the workspace, ran ./eclipse -clean but it doesn't pass the logo. Is there anything left to check / clean?

Answer 1

You need to include the proper SWT plugin for your machine in your run configuration.

1. Click Run -> Run Configurations...
2. Select the Run Configuration that is failing (on the left side)
3. Click the Plug-ins tab
4. In the "type filter text" box, type swt
5. Select the proper swt package for your machine.  For me on OS X this was:
org.eclipse.swt.cocoa.macosx.x86_64

Then run normally and it should work.