java.lang.NullPointerException
   at org.netbeans.modules.refactoring.java.plugins.EncapsulateFieldRefactoringPlugin.getRelevantFiles(EncapsulateFieldRefactoringPlugin.java:507)
   at org.netbeans.modules.refactoring.java.plugins.EncapsulateFieldRefactoringPlugin.prepareEncapsulator(EncapsulateFieldRefactoringPlugin.java:472)
   at org.netbeans.modules.refactoring.java.plugins.EncapsulateFieldsPlugin.prepare(EncapsulateFieldsPlugin.java:198)
   at org.netbeans.modules.refactoring.api.AbstractRefactoring.pluginsPrepare2(AbstractRefactoring.java:437)
   at org.netbeans.modules.refactoring.api.AbstractRefactoring.pluginsPrepare(AbstractRefactoring.java:421)
   at org.netbeans.modules.refactoring.api.AbstractRefactoring.prepare(AbstractRefactoring.java:232)
   at org.netbeans.modules.refactoring.spi.impl.ParametersPanel$Prepare.run(ParametersPanel.java:1020)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1454)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2043)