java.lang.NullPointerException
        at org.netbeans.modules.parsing.impl.indexing.FileObjectIndexable.getURL(FileObjectIndexable.java:97)
        at org.netbeans.modules.parsing.spi.indexing.Indexable.getURL(Indexable.java:93)
        at org.netbeans.modules.java.source.indexing.OnePassCompileWorker.compile(OnePassCompileWorker.java:127)
        at org.netbeans.modules.java.source.indexing.JavaCustomIndexer$1$1.run(JavaCustomIndexer.java:139)
        at org.netbeans.modules.java.source.indexing.JavaCustomIndexer$1$1.run(JavaCustomIndexer.java:124)
Caused: java.io.IOException
        at org.netbeans.modules.java.source.tasklist.TaskCache.refreshTransaction(TaskCache.java:474)
        at org.netbeans.modules.java.source.indexing.JavaCustomIndexer$1.run(JavaCustomIndexer.java:124)
        at org.netbeans.modules.java.source.indexing.JavaCustomIndexer$1.run(JavaCustomIndexer.java:122)
        at org.netbeans.modules.java.source.usages.ClassIndexManager.writeLock(ClassIndexManager.java:100)
        at org.netbeans.modules.java.source.indexing.JavaCustomIndexer.index(JavaCustomIndexer.java:122)
        at org.netbeans.modules.parsing.spi.indexing.Indexable$MyAccessor.index(Indexable.java:165)
        at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.index(RepositoryUpdater.java:1152)
        at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$FileListWork.getDone(RepositoryUpdater.java:1461)
        at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.doTheWork(RepositoryUpdater.java:1345)
        at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task._run(RepositoryUpdater.java:2413)
        at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task.run(RepositoryUpdater.java:2369)
        at org.netbeans.modules.parsing.impl.TaskProcessor$CompilationJob.run(TaskProcessor.java:588)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:417)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:269)
        at java.util.concurrent.FutureTask.run(FutureTask.java:123)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:651)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:676)
        at java.lang.Thread.run(Thread.java:613)