Description Roberto Sanchez Herrera 2011-05-12 16:43:05 EDT

When creating a servlet in a dynamic web project, you will see the following NPE if the source folder selected in the wizard has java build path exclusion patterns that causes the servlet to not be included in the build path. 

!ENTRY org.eclipse.jst.servlet.ui 4 0 2011-05-12 15:22:44.796
!MESSAGE null
!STACK 0
java.lang.NullPointerException
        at org.eclipse.jst.servlet.ui.internal.wizard.NewWebArtifactWizard.openJavaClass(NewWebArtifactWizard.java:79)
        at org.eclipse.jst.servlet.ui.internal.wizard.AddServletWizard.postPerformFinish(AddServletWizard.java:79)
        at org.eclipse.wst.common.frameworks.internal.datamodel.ui.DataModelWizard.performFinish(DataModelWizard.java:201)
        at org.eclipse.jface.wizard.WizardDialog.finishPressed(WizardDialog.java:811)
        at org.eclipse.jface.wizard.WizardDialog.buttonPressed(WizardDialog.java:430)
        at org.eclipse.jface.dialogs.Dialog$2.widgetSelected(Dialog.java:624)
        at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:234)
        at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
        at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053)
        at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4066)
        at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3657)
        at org.eclipse.jface.window.Window.runEventLoop(Window.java:825)
        at org.eclipse.jface.window.Window.open(Window.java:801)
        at org.eclipse.ui.internal.navigator.wizards.WizardShortcutAction.run(WizardShortcutAction.java:98)
        at org.eclipse.jface.action.Action.runWithEvent(Action.java:498)
        at org.eclipse.jface.action.ActionContributionItem.handleWidgetSelection(ActionContributionItem.java:584)
        at org.eclipse.jface.action.ActionContributionItem.access$2(ActionContributionItem.java:501)
        at org.eclipse.jface.action.ActionContributionItem$5.handleEvent(ActionContributionItem.java:411)
        at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
        at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053)
        at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4066)
        at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3657)
        at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2640)
        at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2604)
        at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2438)
        at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:671)
        at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
        at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:664)
        at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
        at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:115)
        at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
        at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
        at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
        at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:369)
        at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:48)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:37)
        at java.lang.reflect.Method.invoke(Method.java:600)
        at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:620)
        at org.eclipse.equinox.launcher.Main.basicRun(Main.java:575)
        at org.eclipse.equinox.launcher.Main.run(Main.java:1408)
        at org.eclipse.equinox.launcher.Main.main(Main.java:1384)

Steps to recreate:

1. Create a dynamic web project.
2. Add a second source folder
3. Go to the Properties -> Java build path -> Source page of the project.
4. Add the exclusion pattern ** to the source folder you created in step 2
5. Open the New servlet wizard
6. Select the source folder you created in step 2
7. Finish the wizard. The NPE is logged, and the servlet class is not opened.