java.lang.NullPointerException
   at com.sun.tools.javac.code.Types.skipTypeVars(Types.java:181)
   at com.sun.tools.javac.comp.Resolve$UnboundMethodReferenceLookupHelper.<init>(Resolve.java:3163)
   at com.sun.tools.javac.comp.Resolve$MethodReferenceLookupHelper.unboundLookup(Resolve.java:3110)
   at com.sun.tools.javac.comp.Resolve.resolveMemberReference(Resolve.java:2716)
   at com.sun.tools.javac.comp.Attr.visitReference(Attr.java:2986)
   at com.sun.tools.javac.tree.JCTree$JCMemberReference.accept(JCTree.java:2155)
   at com.sun.tools.javac.comp.Attr$ResultInfo.attr(Attr.java:496)
   at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:637)
   at com.sun.tools.javac.comp.Attr.visitParens(Attr.java:3245)
   at com.sun.tools.javac.tree.JCTree$JCParens.accept(JCTree.java:1817)
   at com.sun.tools.javac.comp.Attr$ResultInfo.attr(Attr.java:496)
   at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:637)
   at com.sun.tools.javac.comp.DeferredAttr$4.complete(DeferredAttr.java:341)
   at com.sun.tools.javac.comp.ArgumentAttr$ArgumentType.complete(ArgumentAttr.java:361)
   at com.sun.tools.javac.comp.DeferredAttr$DeferredType.check(DeferredAttr.java:302)
   at com.sun.tools.javac.comp.DeferredAttr$DeferredType.check(DeferredAttr.java:289)
   at com.sun.tools.javac.comp.Resolve$MethodResultInfo.check(Resolve.java:1018)
   at com.sun.tools.javac.comp.Resolve$4.checkArg(Resolve.java:841)
   at com.sun.tools.javac.comp.Resolve$AbstractMethodCheck.argumentsAcceptable(Resolve.java:746)
   at com.sun.tools.javac.comp.Resolve$4.argumentsAcceptable(Resolve.java:850)
   at com.sun.tools.javac.comp.Infer.instantiateMethod(Infer.java:186)
   at com.sun.tools.javac.comp.Resolve.rawInstantiate(Resolve.java:577)
   at com.sun.tools.javac.comp.Resolve.checkMethod(Resolve.java:616)
   at com.sun.tools.javac.comp.Attr.checkMethod(Attr.java:4169)
   at com.sun.tools.javac.comp.Attr.checkIdInternal(Attr.java:3955)
   at com.sun.tools.javac.comp.Attr.checkMethodIdInternal(Attr.java:3862)
   at com.sun.tools.javac.comp.Attr.checkMethodId(Attr.java:3841)
   at com.sun.tools.javac.comp.Attr.checkId(Attr.java:3828)
   at com.sun.tools.javac.comp.Attr.visitSelect(Attr.java:3713)
   at com.sun.tools.javac.tree.JCTree$JCFieldAccess.accept(JCTree.java:2075)
   at com.sun.tools.javac.comp.Attr$ResultInfo.attr(Attr.java:496)
   at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:637)
   at com.sun.tools.javac.comp.Attr.visitApply(Attr.java:1937)
   at com.sun.tools.javac.tree.JCTree$JCMethodInvocation.accept(JCTree.java:1604)
   at com.sun.tools.javac.comp.Attr$ResultInfo.attr(Attr.java:496)
   at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:637)
   at com.sun.tools.javac.comp.DeferredAttr$4.complete(DeferredAttr.java:341)
   at com.sun.tools.javac.comp.ArgumentAttr$ArgumentType.complete(ArgumentAttr.java:361)
   at com.sun.tools.javac.comp.DeferredAttr$DeferredType.check(DeferredAttr.java:302)
   at com.sun.tools.javac.comp.DeferredAttr$DeferredType.check(DeferredAttr.java:289)
   at com.sun.tools.javac.comp.Resolve$MethodResultInfo.check(Resolve.java:1018)
   at com.sun.tools.javac.comp.Resolve$4.checkArg(Resolve.java:841)
   at com.sun.tools.javac.comp.Resolve$AbstractMethodCheck.argumentsAcceptable(Resolve.java:746)
   at com.sun.tools.javac.comp.Resolve$4.argumentsAcceptable(Resolve.java:850)
   at com.sun.tools.javac.comp.Infer.instantiateMethod(Infer.java:186)
   at com.sun.tools.javac.comp.Resolve.rawInstantiate(Resolve.java:577)
   at com.sun.tools.javac.comp.Resolve.checkMethod(Resolve.java:616)
   at com.sun.tools.javac.comp.Attr.checkMethod(Attr.java:4169)
   at com.sun.tools.javac.comp.Attr.checkIdInternal(Attr.java:3955)
   at com.sun.tools.javac.comp.Attr.checkMethodIdInternal(Attr.java:3862)
   at com.sun.tools.javac.comp.Attr.checkMethodId(Attr.java:3841)
   at com.sun.tools.javac.comp.Attr.checkId(Attr.java:3828)
   at com.sun.tools.javac.comp.Attr.visitSelect(Attr.java:3713)
   at com.sun.tools.javac.tree.JCTree$JCFieldAccess.accept(JCTree.java:2075)
   at com.sun.tools.javac.comp.Attr$ResultInfo.attr(Attr.java:496)
   at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:637)
   at com.sun.tools.javac.comp.Attr.visitApply(Attr.java:1937)
   at com.sun.tools.javac.tree.JCTree$JCMethodInvocation.accept(JCTree.java:1604)
   at com.sun.tools.javac.comp.Attr$ResultInfo.attr(Attr.java:496)
   at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:637)
   at com.sun.tools.javac.comp.Attr.visitReturn(Attr.java:1789)
   at com.sun.tools.javac.tree.JCTree$JCReturn.accept(JCTree.java:1516)
   at com.sun.tools.javac.comp.Attr$ResultInfo.attr(Attr.java:496)
   at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:637)
   at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:707)
   at com.sun.tools.javac.comp.Attr.attribStats(Attr.java:731)
   at com.sun.tools.javac.comp.Attr.visitBlock(Attr.java:1213)
   at org.netbeans.lib.nbjavac.services.NBAttr.visitBlock(NBAttr.java:82)
   at com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:990)
   at com.sun.tools.javac.comp.Attr$ResultInfo.attr(Attr.java:496)
   at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:637)
   at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:707)
   at com.sun.tools.javac.comp.Attr.visitMethodDef(Attr.java:1099)
   at org.netbeans.lib.nbjavac.services.NBAttr.visitMethodDef(NBAttr.java:76)
   at com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:842)
   at com.sun.tools.javac.comp.Attr$ResultInfo.attr(Attr.java:496)
   at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:637)
   at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:707)
   at com.sun.tools.javac.comp.Attr.attribClassBody(Attr.java:4688)
   at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:4587)
   at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:4515)
   at com.sun.tools.javac.comp.Attr.attrib(Attr.java:4490)
   at com.sun.tools.javac.main.JavaCompiler.attribute(JavaCompiler.java:1295)
   at com.sun.tools.javac.api.JavacTaskImpl$4.process(JavacTaskImpl.java:475)
   at com.sun.tools.javac.api.JavacTaskImpl$Filter.run(JavacTaskImpl.java:607)
   at com.sun.tools.javac.api.JavacTaskImpl.analyze(JavacTaskImpl.java:478)
   at org.netbeans.modules.java.source.indexing.MultiPassCompileWorker.compile(MultiPassCompileWorker.java:267)
   at org.netbeans.modules.java.source.indexing.JavaCustomIndexer.index(JavaCustomIndexer.java:261)
   at org.netbeans.modules.parsing.spi.indexing.Indexable$MyAccessor$2.run(Indexable.java:161)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater.runIndexer(RepositoryUpdater.java:298)
   at org.netbeans.modules.parsing.spi.indexing.Indexable$MyAccessor.index(Indexable.java:159)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.doIndex(RepositoryUpdater.java:2773)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.access$800(RepositoryUpdater.java:2177)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work$1.run(RepositoryUpdater.java:2659)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work$1.run(RepositoryUpdater.java:2657)
   at org.netbeans.modules.parsing.impl.indexing.errors.TaskCache.refreshTransaction(TaskCache.java:565)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.index(RepositoryUpdater.java:2657)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work$3.call(RepositoryUpdater.java:3315)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work$3.call(RepositoryUpdater.java:3281)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$4.run(RepositoryUpdater.java:2150)
   at org.openide.util.lookup.Lookups.executeWith(Lookups.java:304)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater.runInContext(RepositoryUpdater.java:2146)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater.runInContext(RepositoryUpdater.java:2127)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater.access$1500(RepositoryUpdater.java:159)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.scanFiles(RepositoryUpdater.java:3281)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$FileListWork.getDone(RepositoryUpdater.java:3800)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.doTheWork(RepositoryUpdater.java:3435)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task._run(RepositoryUpdater.java:6198)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task.access$4300(RepositoryUpdater.java:5849)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task$2$1.run(RepositoryUpdater.java:6114)
   at org.openide.util.lookup.Lookups.executeWith(Lookups.java:304)
   at org.netbeans.modules.parsing.impl.RunWhenScanFinishedSupport.performScan(RunWhenScanFinishedSupport.java:106)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task$2.call(RepositoryUpdater.java:6110)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task$2.call(RepositoryUpdater.java:6106)
   at org.netbeans.modules.masterfs.filebasedfs.utils.FileChangedManager.priorityIO(FileChangedManager.java:176)
   at org.netbeans.modules.masterfs.providers.ProvidedExtensions.priorityIO(ProvidedExtensions.java:360)
   at org.netbeans.modules.parsing.nb.DataObjectEnvFactory.runPriorityIO(DataObjectEnvFactory.java:141)
   at org.netbeans.modules.parsing.impl.Utilities.runPriorityIO(Utilities.java:88)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task.run(RepositoryUpdater.java:6106)
   at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
   at java.util.concurrent.FutureTask.run(FutureTask.java:266)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1443)
   at org.netbeans.modules.openide.util.GlobalLookup.execute(GlobalLookup.java:68)
   at org.openide.util.lookup.Lookups.executeWith(Lookups.java:303)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2058)