Servlet Error: NullPointer

An unexpected servlet error has occurred.

Stack Trace:



java.lang.NullPointerException at java.base/java.lang.String.compareTo(String.java:1196) at org.apache.lucene.index.TermBuffer.compareTo(TermBuffer.java:35) at org.apache.lucene.index.SegmentTermEnum.scanTo(SegmentTermEnum.java:149) at org.apache.lucene.index.TermInfosReader.scanEnum(TermInfosReader.java:163) at org.apache.lucene.index.TermInfosReader.get(TermInfosReader.java:157) at org.apache.lucene.index.SegmentReader.docFreq(SegmentReader.java:358) at org.apache.lucene.limit.LimIndexReader.docFreq(LimIndexReader.java:166) at org.apache.lucene.search.IndexSearcher.docFreq(IndexSearcher.java:79) at org.apache.lucene.search.Similarity.idf(Similarity.java:457) at org.apache.lucene.search.spans.SpanTermQuery.getSpans(SpanTermQuery.java:87) at org.apache.lucene.search.spans.NearSpans.<init>(NearSpans.java:278) at org.apache.lucene.search.spans.SpanNearQuery.getSpans(SpanNearQuery.java:154) at org.apache.lucene.chunk.SpanDechunkingQuery$1.<init>(SpanDechunkingQuery.java:116) at org.apache.lucene.chunk.SpanDechunkingQuery.getSpans(SpanDechunkingQuery.java:114) at org.apache.lucene.search.spans.SpanWeight.scorer(SpanWeight.java:74) at org.apache.lucene.search.BooleanQuery$BooleanWeight2.scorer(BooleanQuery.java:355) at org.apache.lucene.search.BooleanQuery$BooleanWeight2.scorer(BooleanQuery.java:355) at org.apache.lucene.search.RecordingSearcher.search(RecordingSearcher.java:89) at org.cdlib.xtf.textEngine.DefaultQueryProcessor.processRequest(DefaultQueryProcessor.java:310) at org.cdlib.xtf.textEngine.DefaultQueryProcessor.spellingImprovesResults(DefaultQueryProcessor.java:546) at org.cdlib.xtf.textEngine.DefaultQueryProcessor.spellCheck(DefaultQueryProcessor.java:509) at org.cdlib.xtf.textEngine.DefaultQueryProcessor.processRequest(DefaultQueryProcessor.java:415) at org.cdlib.xtf.crossQuery.CrossQuery.apply(CrossQuery.java:206) at org.cdlib.xtf.crossQuery.CrossQuery.doGet(CrossQuery.java:153) at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) at org.cdlib.xtf.servletBase.TextServlet.service(TextServlet.java:442) at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.base/java.lang.Thread.run(Thread.java:829)