Why do I get a NoClassDefFound error when I try to save my test plan?

Question

I installed apache-jmeter-5.1.1 and java 1.8.0_221 (8), and was walking through the getting started guide to build a web test plan in the GUI. But when I click save to save the Test Plan I receive the below error:

Uncaught Exception java.lang.NoClassDefFoundError: Could not initialize class org.apache.jmeter.gui.util.FileDialoger. See log file for details.

Full Output in debugger:

2019-07-24 15:30:13,306 ERROR o.a.j.JMeter: Uncaught exception: 
java.lang.NoClassDefFoundError: Could not initialize class org.apache.jmeter.gui.util.FileDialoger
    at org.apache.jmeter.gui.action.Save.computeFileName(Save.java:203) ~[ApacheJMeter_core.jar:5.1.1 r1855137]
    at org.apache.jmeter.gui.action.Save.doAction(Save.java:165) ~[ApacheJMeter_core.jar:5.1.1 r1855137]
    at org.apache.jmeter.gui.action.ActionRouter.performAction(ActionRouter.java:88) ~[ApacheJMeter_core.jar:5.1.1 r1855137]
    at org.apache.jmeter.gui.action.ActionRouter.lambda$actionPerformed$0(ActionRouter.java:70) ~[ApacheJMeter_core.jar:5.1.1 r1855137]
    at java.awt.event.InvocationEvent.dispatch(Unknown Source) ~[?:1.8.0_221]
    at java.awt.EventQueue.dispatchEventImpl(Unknown Source) ~[?:1.8.0_221]
    at java.awt.EventQueue.access$500(Unknown Source) ~[?:1.8.0_221]
    at java.awt.EventQueue$3.run(Unknown Source) ~[?:1.8.0_221]
    at java.awt.EventQueue$3.run(Unknown Source) ~[?:1.8.0_221]
    at java.security.AccessController.doPrivileged(Native Method) ~[?:1.8.0_221]
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source) ~[?:1.8.0_221]
    at java.awt.EventQueue.dispatchEvent(Unknown Source) ~[?:1.8.0_221]
    at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) [?:1.8.0_221]
    at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) [?:1.8.0_221]
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) [?:1.8.0_221]
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source) [?:1.8.0_221]
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source) [?:1.8.0_221]
    at java.awt.EventDispatchThread.run(Unknown Source) [?:1.8.0_221]

Any idea how to resolve?

Answer 1

Try the following:

1. Open JMeter -> Options -> Look and Feel -> Select any other theme other than Darcula.
2. Restart JMeter, Create test plan and try to save.
3. Save should work.