java.util.ConcurrentModificationException
   at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372)
   at java.util.AbstractList$Itr.next(AbstractList.java:343)
   at com.googlecode.ivybeans.module.classpath.ClassPathProviderImpl.getFileType(ClassPathProviderImpl.java:110)
   at com.googlecode.ivybeans.module.classpath.ClassPathProviderImpl.findClassPath(ClassPathProviderImpl.java:56)
   at org.netbeans.spi.java.project.support.ClassPathProviderMerger$ProxyClassPathImplementation.checkProviders(ClassPathProviderMerger.java:175)
   at org.netbeans.spi.java.project.support.ClassPathProviderMerger$ProxyClassPathImplementation.<init>(ClassPathProviderMerger.java:151)
   at org.netbeans.spi.java.project.support.ClassPathProviderMerger$CPProvider.findClassPath(ClassPathProviderMerger.java:108)
   at org.netbeans.modules.java.project.ProjectClassPathProvider.findClassPath(ProjectClassPathProvider.java:73)
   at org.netbeans.api.java.classpath.ClassPath.getClassPath(ClassPath.java:593)
   at org.netbeans.modules.java.source.usages.BuildArtifactMapperImpl$FileBuildQueryImpl.getStatus(BuildArtifactMapperImpl.java:678)
   at org.netbeans.api.queries.FileBuiltQuery.getStatus(FileBuiltQuery.java:102)
   at org.netbeans.modules.java.JavaNode$BuildStatusTask.run(JavaNode.java:329)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1418)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1957)