Gradle + Eclipse WTP でサードパーティライブラリのソースが見えるようにする

build.gradle

eclipse {

  classpath {
    file {
      whenMerged { classpath ->
        def webContainer = classpath.entries.find { it.path == 'org.eclipse.jst.j2ee.internal.web.container' }
        if (webContainer != null) {
          def projects = classpath.entries.findAll { it instanceof org.gradle.plugins.ide.eclipse.model.ProjectDependency }
          def others = classpath.entries.findAll { it != webContainer }
          others.removeAll(projects);
          classpath.entries = others + webContainer + projects
        }
      }
    }
  }

}