CodenameOne Gui Builder NPE Crash in Intellij Idea - intellij-idea

Question

* UPDATES BELOW *
perhaps I'm doing something wrong here but if so, It's not clear to me what. Is this a known issue? Should I be looking somewhere specific to find out if there are unmet dependencies etc (like Java version or IDE version or plugins or ?). Please help.
Scenario:
I've got the latest IntelliJ Idea version (14.1.7)
Java version is 1.8.0_91 confirmed from terminal in IDE using java
-version)
Just updated to CN1 plugin version 3.7.1
Just started a new project to play with the new GUI Builder.
Here's the steps to reproduce:
I right-click on the package and select "New Form" and give it a name
The form java file and the .gui file are created
I right-click on the java file and select "CN1->Gui Builder"
then Idea barfs out an error event (NoSuchMethodError) with the following details:, and the GUI Builder doesn't show up
Stack Trace:
com.intellij.openapi.vfs.VfsUtil.getChildren(Lcom/intellij/openapi/vfs/VirtualFile;Lcom/intellij/openapi/vfs/VirtualFileFilter;)Ljava/util/List;
java.lang.NoSuchMethodError: com.intellij.openapi.vfs.VfsUtil.getChildren(Lcom/intellij/openapi/vfs/VirtualFile;Lcom/intellij/openapi/vfs/VirtualFileFilter;)Ljava/util/List;
at com.codename1.plugin.intellij.actions.GUIBuilderAction.actionPerformed(GUIBuilderAction.java:73)
at com.intellij.openapi.actionSystem.ex.ActionUtil.performActionDumbAware(ActionUtil.java:182)
at com.intellij.openapi.actionSystem.impl.ActionMenuItem$ActionTransmitter$1.run(ActionMenuItem.java:312)
at com.intellij.openapi.wm.impl.FocusManagerImpl.runOnOwnContext(FocusManagerImpl.java:958)
at com.intellij.openapi.wm.impl.IdeFocusManagerImpl.runOnOwnContext(IdeFocusManagerImpl.java:124)
at com.intellij.openapi.actionSystem.impl.ActionMenuItem$ActionTransmitter.actionPerformed(ActionMenuItem.java:282)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at com.intellij.openapi.actionSystem.impl.ActionMenuItem.fireActionPerformed(ActionMenuItem.java:109)
at com.intellij.ui.plaf.beg.BegMenuItemUI.doClick(BegMenuItemUI.java:512)
at com.intellij.ui.plaf.beg.BegMenuItemUI.access$300(BegMenuItemUI.java:44)
at com.intellij.ui.plaf.beg.BegMenuItemUI$MyMouseInputHandler.mouseReleased(BegMenuItemUI.java:532)
at java.awt.Component.processMouseEvent(Component.java:6535)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at java.awt.Component.processEvent(Component.java:6300)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4891)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4713)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
at java.awt.Container.dispatchEventImpl(Container.java:2280)
at java.awt.Window.dispatchEventImpl(Window.java:2750)
at java.awt.Component.dispatchEvent(Component.java:4713)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.awt.EventQueue$4.run(EventQueue.java:729)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at com.intellij.ide.IdeEventQueue.defaultDispatchEvent(IdeEventQueue.java:734)
at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:565)
at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:382)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
* UPDATE *
Based on some good advice, I realized just how old my version of Idea was, so I've upgraded to 2017.1.4. I removed and reinstalled the 3.7 plugin, and my test project still fails to launch GUI Builder, but now has a different error and stack trace:
java.lang.IndexOutOfBoundsException: Index: 0
at com.intellij.util.containers.ContainerUtilRt$EmptyList.get(ContainerUtilRt.java:308)
at com.codename1.plugin.intellij.actions.GUIBuilderAction.actionPerformed(GUIBuilderAction.java:74)
at com.intellij.openapi.actionSystem.ex.ActionUtil$1.run(ActionUtil.java:215)
at com.intellij.openapi.actionSystem.ex.ActionUtil.performActionDumbAware(ActionUtil.java:232)
at com.intellij.openapi.actionSystem.impl.ActionMenuItem$ActionTransmitter.lambda$actionPerformed$0(ActionMenuItem.java:309)
at com.intellij.openapi.wm.impl.FocusManagerImpl.runOnOwnContext(FocusManagerImpl.java:929)
at com.intellij.openapi.wm.impl.IdeFocusManagerImpl.runOnOwnContext(IdeFocusManagerImpl.java:136)
at com.intellij.openapi.actionSystem.impl.ActionMenuItem$ActionTransmitter.actionPerformed(ActionMenuItem.java:299)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at com.intellij.openapi.actionSystem.impl.ActionMenuItem.lambda$fireActionPerformed$0(ActionMenuItem.java:116)
at com.intellij.openapi.application.TransactionGuardImpl.runSyncTransaction(TransactionGuardImpl.java:86)
at com.intellij.openapi.application.TransactionGuardImpl.lambda$submitTransaction$1(TransactionGuardImpl.java:109)
at com.intellij.openapi.application.TransactionGuardImpl.submitTransaction(TransactionGuardImpl.java:118)
at com.intellij.openapi.application.TransactionGuard.submitTransaction(TransactionGuard.java:122)
at com.intellij.openapi.actionSystem.impl.ActionMenuItem.fireActionPerformed(ActionMenuItem.java:116)
at com.intellij.ui.plaf.beg.BegMenuItemUI.doClick(BegMenuItemUI.java:513)
at com.intellij.ui.plaf.beg.BegMenuItemUI.access$300(BegMenuItemUI.java:45)
at com.intellij.ui.plaf.beg.BegMenuItemUI$MyMouseInputHandler.mouseReleased(BegMenuItemUI.java:533)
at java.awt.Component.processMouseEvent(Component.java:6541)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at java.awt.Component.processEvent(Component.java:6306)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4897)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4719)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
at java.awt.Container.dispatchEventImpl(Container.java:2280)
at java.awt.Window.dispatchEventImpl(Window.java:2746)
at java.awt.Component.dispatchEvent(Component.java:4719)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:764)
at java.awt.EventQueue.access$500(EventQueue.java:98)
at java.awt.EventQueue$3.run(EventQueue.java:715)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:90)
at java.awt.EventQueue$4.run(EventQueue.java:737)
at java.awt.EventQueue$4.run(EventQueue.java:735)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:734)
at com.intellij.ide.IdeEventQueue.defaultDispatchEvent(IdeEventQueue.java:827)
at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:651)
at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:365)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

Answer 1

Apparently, the plug-in version 3.7.1 you have installed is not compatible with IntelliJ IDEA 14.1.7. Developer has mistakenly specified that it's compatible without performing the real tests. Since 14.1.7 is pretty old, no one has noticed this problem before. So, either update to the current IntelliJ IDEA version, try some older plug-in version installed manually or file a bug to the plug-in developer.
As for the second problem, please check this answer.

Answer 2

It turns out that my config of Idea had an older Java (Android!) SDK configured as a default for new projects. This default was causing new project CREATION to do something strange which made it unable to use the GUI Builder. Fixing the incorrect SDK in my project config alone didn't make GUI Builder work in the pre-existing project; rather, I needed to create a new project with the correct SDK set and then it started working. Perhaps there could have been a step to force CodenameOne to "recreate" or "regenrate" the project after the fix, but it was not apparent to me.
#Shai Almog, I hope this at least gives you some clues as to how this issue happened so you can prevent it from affecting others in the future. For now My issue is resolve. thanks for the help all.