org.apache.lucene.index.CorruptIndexException: Unknown format version: -9
   at org.apache.lucene.index.SegmentInfos.read(SegmentInfos.java:225)
   at org.apache.lucene.index.SegmentInfos$1.doBody(SegmentInfos.java:275)
   at org.apache.lucene.index.SegmentInfos$FindSegmentsFile.run(SegmentInfos.java:653)
   at org.apache.lucene.index.SegmentInfos.read(SegmentInfos.java:272)
   at org.apache.lucene.index.IndexWriter.init(IndexWriter.java:1088)
   at org.apache.lucene.index.IndexWriter.<init>(IndexWriter.java:686)
   at org.netbeans.modules.parsing.impl.indexing.lucene.LuceneIndex.flush(LuceneIndex.java:633)
   at org.netbeans.modules.parsing.impl.indexing.lucene.LuceneIndex.access$700(LuceneIndex.java:91)
   at org.netbeans.modules.parsing.impl.indexing.lucene.LuceneIndex$1.run(LuceneIndex.java:175)
   at org.netbeans.modules.parsing.impl.indexing.lucene.LuceneIndex$1.run(LuceneIndex.java:146)
   at org.netbeans.modules.parsing.impl.indexing.lucene.LuceneIndexManager.writeAccess(LuceneIndexManager.java:83)
   at org.netbeans.modules.parsing.impl.indexing.lucene.LuceneIndex.store(LuceneIndex.java:146)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.scanFinished(RepositoryUpdater.java:1553)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$AbstractRootsWork.scanSource(RepositoryUpdater.java:3246)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$AbstractRootsWork.scanSources(RepositoryUpdater.java:3129)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$RootsWork.getDone(RepositoryUpdater.java:2878)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.doTheWork(RepositoryUpdater.java:2018)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task._run(RepositoryUpdater.java:3616)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task.run(RepositoryUpdater.java:3556)
   at org.netbeans.modules.parsing.impl.TaskProcessor$CompilationJob.run(TaskProcessor.java:587)
   at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
   at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
   at java.util.concurrent.FutureTask.run(FutureTask.java:138)
   at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
   at java.lang.Thread.run(Thread.java:619)