Exception in Codename One Plugin in IntelliJ - intellij-idea

Question

I downloaded updates to IntelliJ Idea and the Codename One plugin yesterday (02 March 2018), now I can't create a new form:
I started a new Codename One project, using the Hello World template. I compiled and ran it. Without changing any code I right-clicked on my src folder and chose New /Codename One Form (AutoLayout).
IntelliJ IDEA 2017.3.4 (Community Edition)
Build #IC-173.4548.28, built on January 30, 2018
JRE: 1.8.0_152-release-1024-b11 x86_64
JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
Mac OS X 10.13.3
Codename One plugin 3.8.3
The error messages:
null
java.lang.NullPointerException
at com.codename1.plugin.intellij.filesystem.ResourceEditorMonitor$2.run(ResourceEditorMonitor.java:235)
at com.intellij.openapi.application.RunResult.run(RunResult.java:35)
at com.intellij.openapi.application.WriteAction.execute(WriteAction.java:38)
at com.codename1.plugin.intellij.filesystem.ResourceEditorMonitor.updateGUIBuilderFile(ResourceEditorMonitor.java:263)
at com.codename1.plugin.intellij.filesystem.ResourceEditorMonitor$3.contentsChanged(ResourceEditorMonitor.java:282)
at sun.reflect.GeneratedMethodAccessor90.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.intellij.util.EventDispatcher.dispatch(EventDispatcher.java:99)
at com.intellij.util.EventDispatcher.access$200(EventDispatcher.java:35)
at com.intellij.util.EventDispatcher$2.invoke(EventDispatcher.java:79)
at com.sun.proxy.$Proxy17.contentsChanged(Unknown Source)
at com.intellij.openapi.vfs.impl.BulkVirtualFileListenerAdapter.fireAfter(BulkVirtualFileListenerAdapter.java:65)
at com.intellij.openapi.vfs.impl.BulkVirtualFileListenerAdapter.after(BulkVirtualFileListenerAdapter.java:56)
at sun.reflect.GeneratedMethodAccessor28.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.intellij.util.messages.impl.MessageBusConnectionImpl.deliverMessage(MessageBusConnectionImpl.java:117)
at com.intellij.util.messages.impl.MessageBusImpl.doPumpMessages(MessageBusImpl.java:449)
at com.intellij.util.messages.impl.MessageBusImpl.pumpWaitingBuses(MessageBusImpl.java:410)
at com.intellij.util.messages.impl.MessageBusImpl.pumpMessages(MessageBusImpl.java:399)
at com.intellij.util.messages.impl.MessageBusImpl.sendMessage(MessageBusImpl.java:380)
at com.intellij.util.messages.impl.MessageBusImpl.access$200(MessageBusImpl.java:45)
at com.intellij.util.messages.impl.MessageBusImpl$2.invoke(MessageBusImpl.java:231)
at com.sun.proxy.$Proxy15.after(Unknown Source)
at com.intellij.openapi.vfs.newvfs.persistent.PersistentFSImpl$2.close(PersistentFSImpl.java:651)
at com.intellij.openapi.vfs.VirtualFile.setBinaryContent(VirtualFile.java:570)
at com.intellij.openapi.vfs.newvfs.impl.VirtualFileImpl.setBinaryContent(VirtualFileImpl.java:166)
at com.intellij.openapi.vfs.VirtualFile.setBinaryContent(VirtualFile.java:562)
at com.intellij.openapi.vfs.newvfs.impl.VirtualFileImpl.setBinaryContent(VirtualFileImpl.java:172)
at com.intellij.openapi.vfs.VirtualFile.setBinaryContent(VirtualFile.java:558)
at com.intellij.openapi.vfs.VfsUtil.saveText(VfsUtil.java:53)
at com.codename1.plugin.intellij.actions.NewGuiBuilderFormAction$2.run(NewGuiBuilderFormAction.java:104)
at com.intellij.openapi.application.RunResult.run(RunResult.java:35)
at com.intellij.openapi.application.WriteAction.execute(WriteAction.java:38)
at com.codename1.plugin.intellij.actions.NewGuiBuilderFormAction.actionPerformed(NewGuiBuilderFormAction.java:106)
at com.intellij.openapi.actionSystem.ex.ActionUtil$1.run(ActionUtil.java:220)
at com.intellij.openapi.actionSystem.ex.ActionUtil.performActionDumbAware(ActionUtil.java:237)
at com.intellij.openapi.actionSystem.impl.ActionMenuItem$ActionTransmitter.lambda$actionPerformed$0(ActionMenuItem.java:321)
at com.intellij.openapi.wm.impl.FocusManagerImpl.runOnOwnContext(FocusManagerImpl.java:911)
at com.intellij.openapi.wm.impl.IdeFocusManagerImpl.runOnOwnContext(IdeFocusManagerImpl.java:136)
at com.intellij.openapi.actionSystem.impl.ActionMenuItem$ActionTransmitter.actionPerformed(ActionMenuItem.java:311)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at com.intellij.openapi.actionSystem.impl.ActionMenuItem.lambda$fireActionPerformed$0(ActionMenuItem.java:130)
at com.intellij.openapi.application.TransactionGuardImpl.runSyncTransaction(TransactionGuardImpl.java:88)
at com.intellij.openapi.application.TransactionGuardImpl.lambda$submitTransaction$1(TransactionGuardImpl.java:111)
at com.intellij.openapi.application.TransactionGuardImpl.submitTransaction(TransactionGuardImpl.java:120)
at com.intellij.openapi.application.TransactionGuard.submitTransaction(TransactionGuard.java:122)
at com.intellij.openapi.actionSystem.impl.ActionMenuItem.fireActionPerformed(ActionMenuItem.java:130)
at com.intellij.ui.plaf.beg.BegMenuItemUI.doClick(BegMenuItemUI.java:521)
at com.intellij.ui.plaf.beg.BegMenuItemUI.access$300(BegMenuItemUI.java:48)
at com.intellij.ui.plaf.beg.BegMenuItemUI$MyMouseInputHandler.mouseReleased(BegMenuItemUI.java:541)
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:2237)
at java.awt.Component.dispatchEventImpl(Component.java:4897)
at java.awt.Container.dispatchEventImpl(Container.java:2295)
at java.awt.Component.dispatchEvent(Component.java:4719)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4889)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4526)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4467)
at java.awt.Container.dispatchEventImpl(Container.java:2281)
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:822)
at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:646)
at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:366)
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

There seems to be a bug there. First off make sure to create the GUI builder file in a package and not in the src directory directly.
If you right click the project and select Codename One -> Refresh cn1libs it should workaround the issue.
This issue is triggered because some directories haven't been created yet and refresh cn1libs will force a build/directory creation.