Hello,
We ve got an unexpected execution error running 7.9.2 & PMD plugin 3.2.1 that I cannot explain :
08:18:34 INFO: PMD configuration: <path_to_conffile>/.scannerwork/pmd.xml
08:18:34 ERROR: Fail to execute PMD. Following file is ignored: <path_to_sourcecode>/<classname>.java
08:18:34 net.sourceforge.pmd.PMDException: Error while processing file:<path_to_sourcecode>/<classname>.java
08:18:34 at net.sourceforge.pmd.SourceCodeProcessor.processSourceCode(SourceCodeProcessor.java:102)
08:18:34 at net.sourceforge.pmd.SourceCodeProcessor.processSourceCode(SourceCodeProcessor.java:51)
08:18:34 at org.sonar.plugins.pmd.PmdTemplate.process(PmdTemplate.java:101)
08:18:34 at org.sonar.plugins.pmd.PmdExecutor.executeRules(PmdExecutor.java:131)
08:18:34 at org.sonar.plugins.pmd.PmdExecutor.executePmd(PmdExecutor.java:98)
08:18:34 at org.sonar.plugins.pmd.PmdExecutor.execute(PmdExecutor.java:80)
08:18:34 at org.sonar.plugins.pmd.PmdSensor.execute(PmdSensor.java:71)
08:18:34 at org.sonar.scanner.sensor.AbstractSensorWrapper.analyse(AbstractSensorWrapper.java:48)
08:18:34 at org.sonar.scanner.sensor.ModuleSensorsExecutor.execute(ModuleSensorsExecutor.java:85)
08:18:34 at org.sonar.scanner.sensor.ModuleSensorsExecutor.lambda$execute$1(ModuleSensorsExecutor.java:59)
08:18:34 at org.sonar.scanner.sensor.ModuleSensorsExecutor.withModuleStrategy(ModuleSensorsExecutor.java:77)
08:18:34 at org.sonar.scanner.sensor.ModuleSensorsExecutor.execute(ModuleSensorsExecutor.java:59)
08:18:34 at org.sonar.scanner.scan.ModuleScanContainer.doAfterStart(ModuleScanContainer.java:82)
08:18:34 at org.sonar.core.platform.ComponentContainer.startComponents(ComponentContainer.java:136)
08:18:34 at org.sonar.core.platform.ComponentContainer.execute(ComponentContainer.java:122)
08:18:34 at org.sonar.scanner.scan.ProjectScanContainer.scan(ProjectScanContainer.java:400)
08:18:34 at org.sonar.scanner.scan.ProjectScanContainer.scanRecursively(ProjectScanContainer.java:395)
08:18:34 at org.sonar.scanner.scan.ProjectScanContainer.doAfterStart(ProjectScanContainer.java:358)
08:18:34 at org.sonar.core.platform.ComponentContainer.startComponents(ComponentContainer.java:136)
08:18:34 at org.sonar.core.platform.ComponentContainer.execute(ComponentContainer.java:122)
08:18:34 at org.sonar.scanner.bootstrap.GlobalContainer.doAfterStart(GlobalContainer.java:141)
08:18:34 at org.sonar.core.platform.ComponentContainer.startComponents(ComponentContainer.java:136)
08:18:34 at org.sonar.core.platform.ComponentContainer.execute(ComponentContainer.java:122)
08:18:34 at org.sonar.batch.bootstrapper.Batch.doExecute(Batch.java:73)
08:18:34 at org.sonar.batch.bootstrapper.Batch.execute(Batch.java:67)
08:18:34 at org.sonarsource.scanner.api.internal.batch.BatchIsolatedLauncher.execute(BatchIsolatedLauncher.java:46)
08:18:34 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
08:18:34 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
08:18:34 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
08:18:34 at java.lang.reflect.Method.invoke(Method.java:498)
08:18:34 at org.sonarsource.scanner.api.internal.IsolatedLauncherProxy.invoke(IsolatedLauncherProxy.java:60)
08:18:34 at com.sun.proxy.$Proxy0.execute(Unknown Source)
08:18:34 at org.sonarsource.scanner.api.EmbeddedScanner.doExecute(EmbeddedScanner.java:185)
08:18:34 at org.sonarsource.scanner.api.EmbeddedScanner.execute(EmbeddedScanner.java:137)
08:18:34 at org.sonarsource.scanner.cli.Main.execute(Main.java:112)
08:18:34 at org.sonarsource.scanner.cli.Main.execute(Main.java:75)
08:18:34 at org.sonarsource.scanner.cli.Main.main(Main.java:61)
08:18:34 Caused by: java.lang.NullPointerException: null
08:18:34 at net.sourceforge.pmd.lang.java.typeresolution.ClassTypeResolver.populateType(ClassTypeResolver.java:1361)
08:18:34 at net.sourceforge.pmd.lang.java.typeresolution.ClassTypeResolver.visit(ClassTypeResolver.java:262)
08:18:34 at net.sourceforge.pmd.lang.java.ast.ASTClassOrInterfaceType.jjtAccept(ASTClassOrInterfaceType.java:32)
08:18:34 at net.sourceforge.pmd.lang.java.ast.AbstractJavaNode.childrenAccept(AbstractJavaNode.java:60)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:11)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:436)
08:18:34 at net.sourceforge.pmd.lang.java.typeresolution.ClassTypeResolver.visit(ClassTypeResolver.java:1156)
08:18:34 at net.sourceforge.pmd.lang.java.ast.ASTAllocationExpression.jjtAccept(ASTAllocationExpression.java:28)
08:18:34 at net.sourceforge.pmd.lang.java.ast.AbstractJavaNode.childrenAccept(AbstractJavaNode.java:60)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:11)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:401)
08:18:34 at net.sourceforge.pmd.lang.java.typeresolution.ClassTypeResolver.visit(ClassTypeResolver.java:1035)
08:18:34 at net.sourceforge.pmd.lang.java.ast.ASTPrimaryPrefix.jjtAccept(ASTPrimaryPrefix.java:42)
08:18:34 at net.sourceforge.pmd.lang.java.typeresolution.ClassTypeResolver.visit(ClassTypeResolver.java:869)
08:18:34 at net.sourceforge.pmd.lang.java.ast.ASTPrimaryExpression.jjtAccept(ASTPrimaryExpression.java:22)
08:18:34 at net.sourceforge.pmd.lang.java.ast.AbstractJavaNode.childrenAccept(AbstractJavaNode.java:60)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:11)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:296)
08:18:34 at net.sourceforge.pmd.lang.java.typeresolution.ClassTypeResolver.visit(ClassTypeResolver.java:729)
08:18:34 at net.sourceforge.pmd.lang.java.ast.ASTExpression.jjtAccept(ASTExpression.java:34)
08:18:34 at net.sourceforge.pmd.lang.java.ast.AbstractJavaNode.childrenAccept(AbstractJavaNode.java:60)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:11)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:226)
08:18:34 at net.sourceforge.pmd.lang.java.ast.ASTVariableInitializer.jjtAccept(ASTVariableInitializer.java:22)
08:18:34 at net.sourceforge.pmd.lang.java.ast.AbstractJavaNode.childrenAccept(AbstractJavaNode.java:60)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:11)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:216)
08:18:34 at net.sourceforge.pmd.lang.java.typeresolution.ClassTypeResolver.visit(ClassTypeResolver.java:602)
08:18:34 at net.sourceforge.pmd.lang.java.ast.ASTVariableDeclarator.jjtAccept(ASTVariableDeclarator.java:37)
08:18:34 at net.sourceforge.pmd.lang.java.ast.AbstractJavaNode.childrenAccept(AbstractJavaNode.java:60)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:11)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:211)
08:18:34 at net.sourceforge.pmd.lang.java.typeresolution.ClassTypeResolver.visit(ClassTypeResolver.java:595)
08:18:34 at net.sourceforge.pmd.lang.java.ast.ASTFieldDeclaration.jjtAccept(ASTFieldDeclaration.java:56)
08:18:34 at net.sourceforge.pmd.lang.java.ast.AbstractJavaNode.childrenAccept(AbstractJavaNode.java:60)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:11)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:56)
08:18:34 at net.sourceforge.pmd.lang.java.ast.ASTClassOrInterfaceBodyDeclaration.jjtAccept(ASTClassOrInterfaceBodyDeclaration.java:43)
08:18:34 at net.sourceforge.pmd.lang.java.ast.AbstractJavaNode.childrenAccept(AbstractJavaNode.java:60)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:11)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:51)
08:18:34 at net.sourceforge.pmd.lang.java.ast.ASTClassOrInterfaceBody.jjtAccept(ASTClassOrInterfaceBody.java:32)
08:18:34 at net.sourceforge.pmd.lang.java.ast.AbstractJavaNode.childrenAccept(AbstractJavaNode.java:60)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:11)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:21)
08:18:34 at net.sourceforge.pmd.lang.java.ast.ASTClassOrInterfaceDeclaration.jjtAccept(ASTClassOrInterfaceDeclaration.java:55)
08:18:34 at net.sourceforge.pmd.lang.java.ast.AbstractJavaNode.childrenAccept(AbstractJavaNode.java:60)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:11)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:206)
08:18:34 at net.sourceforge.pmd.lang.java.typeresolution.ClassTypeResolver.visit(ClassTypeResolver.java:242)
08:18:34 at net.sourceforge.pmd.lang.java.ast.ASTTypeDeclaration.jjtAccept(ASTTypeDeclaration.java:37)
08:18:34 at net.sourceforge.pmd.lang.java.ast.AbstractJavaNode.childrenAccept(AbstractJavaNode.java:60)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:11)
08:18:34 at net.sourceforge.pmd.lang.java.ast.JavaParserVisitorAdapter.visit(JavaParserVisitorAdapter.java:181)
08:18:34 at net.sourceforge.pmd.lang.java.typeresolution.ClassTypeResolver.visit(ClassTypeResolver.java:213)
08:18:34 at net.sourceforge.pmd.lang.java.ast.ASTCompilationUnit.jjtAccept(ASTCompilationUnit.java:41)
08:18:34 at net.sourceforge.pmd.lang.java.typeresolution.TypeResolutionFacade.initializeWith(TypeResolutionFacade.java:18)
08:18:34 at net.sourceforge.pmd.lang.java.AbstractJavaHandler$5.start(AbstractJavaHandler.java:109)
08:18:34 at net.sourceforge.pmd.SourceCodeProcessor.usesTypeResolution(SourceCodeProcessor.java:153)
08:18:34 at net.sourceforge.pmd.SourceCodeProcessor.processSource(SourceCodeProcessor.java:180)
08:18:34 at net.sourceforge.pmd.SourceCodeProcessor.processSourceCode(SourceCodeProcessor.java:96)
08:18:34 ... 36 common frames omitted
08:18:34
08:18:36 INFO: PMD configuration: <path_to_conffile>/.scannerwork/pmd-unit-tests.xml
08:18:36 INFO: Execute PMD 6.10.0 (done) | time=2076ms
08:18:36 INFO: Sensor PmdSensor [pmd] (done) | time=2080ms
Any idea of what might cause this issue and how to fix it ?
Does anybody already had this kind of behavior with PMD plugin ?
By the way, we are using Java 8 and the asscociated pmd sonarqube property is well set (sonar.java.source=1.8).
Thanks for helping 
Vincent