SonarQube fails to restart during plugin development

Question

I'm developing a plugin for SonarQube 4.5.4 / 5.0.1. I would like to use sonar-dev plugin to upload a JAR file and quickly restart SQ server. Plugin uses REST API (/api/system/restart), which is enabled by setting sonar.dev=true property.

Here's config:

<plugin>
    <groupId>org.codehaus.sonar</groupId>
    <artifactId>sonar-dev-maven-plugin</artifactId>
    <version>1.8</version>
    <configuration>
        <sonarHome>F:\sonarqube-5.1\sonarqube-5.1</sonarHome>
    </configuration>
</plugin>

The problem is that server crashes after each restart attempt and I have to restart it manually, which is frustrating and drains my productivity. Here's stacktrace that is returned on each following request after "restart".

org.jruby.exceptions.RaiseException: (NoMethodError) undefined method `controllers' for nil:NilClass
    at org.jruby.RubyKernel.method_missing(org/jruby/RubyKernel.java:255)
    at RUBY.method_missing(F:/sonarqube-5.1/sonarqube-5.1/web/WEB-INF/gems/gems/activesupport-2.3.15/lib/active_support/whiny_nil.rb:52)
    at RUBY.add_java_ws_routes(F:/sonarqube-5.1/sonarqube-5.1/web/WEB-INF/config/../lib/java_ws_routing.rb:34)
    at RUBY.reload(F:/sonarqube-5.1/sonarqube-5.1/web/WEB-INF/config/../lib/java_ws_routing.rb:58)
    at RUBY.reload_application(F:/sonarqube-5.1/sonarqube-5.1/web/WEB-INF/gems/gems/actionpack-2.3.15/lib/action_controller/dispatcher.rb:58)
    at RUBY.run(F:/sonarqube-5.1/sonarqube-5.1/web/WEB-INF/gems/gems/actionpack-2.3.15/lib/action_controller/reloader.rb:42)
    at RUBY.call(F:/sonarqube-5.1/sonarqube-5.1/web/WEB-INF/gems/gems/actionpack-2.3.15/lib/action_controller/dispatcher.rb:108)
    at RUBY.serve_rails(file:/F:/sonarqube-5.1/sonarqube-5.1/lib/server/jruby-rack-1.1.13.2.jar!/rack/adapter/rails.rb:34)
    at RUBY.call(file:/F:/sonarqube-5.1/sonarqube-5.1/lib/server/jruby-rack-1.1.13.2.jar!/rack/adapter/rails.rb:39)
    at RUBY.call(file:/F:/sonarqube-5.1/sonarqube-5.1/lib/server/jruby-rack-1.1.13.2.jar!/rack/handler/servlet.rb:22)

And here's what happens in logs starting from line 71.

According to @Simon Brandhof, it may be connected with class loader, that locks files. Any clue or workaround be be much appreciated.

Answer 1

The Java plugin seems to lock its classloader. Uninstalling it, by deleting extensions/plugins/sonar-java-plugin-3.0.jar, should fix the issue.