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NoClassDefFoundError: org/apache/commons/lang/WordUtils on IntelliJ IDEA 2026.2 #36

Description

@vasylplus12

Environment

  • IntelliJ IDEA: 2026.2
  • OS: Linux
  • CamelCase plugin: 3.0.12

Problem

CamelCase fails when triggering a case conversion (Shift+Alt+U).

IntelliJ reports:

java.lang.NoClassDefFoundError: org/apache/commons/lang/WordUtils
at de.netnexus.CamelCasePlugin.conversion.transform(...)
at de.netnexus.CamelCasePlugin.CamelCaseEditorActionHandler.before(...)
...

The plugin appears to depend on Apache Commons Lang 2.x WordUtils, but that
class is not included in the distributed CamelCasePlugin.jar and is apparently
no longer available from the IntelliJ Platform classpath.

I verified the plugin JAR:

jar tf CamelCasePlugin.jar | grep 'org/apache/commons/lang/WordUtils.class'

There was no matching class.

Reproduction

  1. Install CamelCase 3.0.12 in IntelliJ IDEA 2026.2.
  2. Open any editable file.
  3. Select/place the caret on some text.
  4. Trigger CamelCase conversion with Shift+Alt+U.
  5. The plugin throws NoClassDefFoundError.

Expected

CamelCase should perform the case conversion normally.

Actual

java.lang.NoClassDefFoundError:
org/apache/commons/lang/WordUtils

Workaround / probable cause

As a workaround I downloaded commons-lang:commons-lang:2.6 and manually
added org/apache/commons/lang/* into CamelCasePlugin.jar.

This makes the missing WordUtils class available to the plugin.

It looks like CamelCase 3.0.12 relies on Commons Lang 2.x being provided by
the IntelliJ Platform instead of packaging the dependency with the plugin.

The plugin should either:

  1. package the required Commons Lang dependency, or
  2. migrate away from org.apache.commons.lang.WordUtils.

I can provide the complete IntelliJ stack trace if needed.

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