Error With ForkedTomcatServer in Grails

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Recently I had an issue with just about all of the Grails apps on my machine.

When I tried to run them, I was getting this error:

| Packaging Grails application.....
| Error Tomcat plugin classes JAR grails-plugin-tomcat-7.0.42.jar not found
| Running Grails application
Error: Could not find or load main class org.grails.plugins.tomcat.fork.For­kedTomcatServer
| Error Forked Grails VM exited with error

The number for the jar file would be different for different versions of Grails.

What I finally did to get rid of the error was:

  1. Run “grails clean; grails compile; grails list-plugins”
  2. Comment out the line for the Tomcat plugin in BuildConfig.groovy
  3. Run “grails clean; grails compile; grails list-plugins” again
  4. Uncomment the line for the Tomcat plugin
  5. Run “grails clean; grails compile; grails list-plugins” again

Maybe the first “grails clean; grails compile” is unnecessary. But this seemed to work.

I have no idea what caused it. It happened with various versions of Grails. I had no problem with new Grails apps, or with apps downloaded from Github.

You’re welcome.