title: When launching Codename One's Gui Builder, on Eclipse, I get the error "Unhandled event loop exception"
body: <p>As per tutorials I set up the GUI Builder with the file wizard. Then when I ctrl-click the form created and try to open it with the GUI Builder nothing happens
  other than the error message <code>"Unhandled event loop exception"; Plug-in= "org.eclipse.ui"</code> with the Date and time given:<code>12/04/2020, 20:39</code>. </p>
  
  <p>I am using </p>
  
  <pre><code>mac: Version 10.15.1 
  Eclipse: Oxygen.3a Release (4.7.3a) 
  </code></pre>
  
  <p>I also can't open Codename One Settings on project... I can open the ResourceEditorApp, via Theme.res file.my current version is 1.1 Build #: 20171229</p>
  
  <p>With regard to the error and greg-449 request:</p>
  
  <p>The "Exception Stack Trace" field:</p>
  
  <pre><code>    java.lang.NullPointerException
      at                codenameoneplugin.GUIBuilderLauncher.open(GUIBuilderLauncher.java:40)
  at       org.eclipse.ui.internal.WorkbenchPage$31.run(WorkbenchPage.java:5397)
   at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
  at org.eclipse.ui.internal.WorkbenchPage.openExternalEditor(WorkbenchPage.java:5388)
  at org.eclipse.ui.internal.WorkbenchPage.busyOpenEditor(WorkbenchPage.java:3253)
  at org.eclipse.ui.internal.WorkbenchPage.access$25(WorkbenchPage.java:3176)
  at org.eclipse.ui.internal.WorkbenchPage$10.run(WorkbenchPage.java:3158)
  at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
  at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:3153)
  at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:3117)
  at org.eclipse.ui.actions.OpenWithMenu.openEditor(OpenWithMenu.java:323)
  at org.eclipse.ui.actions.OpenWithMenu.lambda$0(OpenWithMenu.java:180)
  at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:86)
  at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4258)
  at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1502)
  at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1525)
  at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1510)
  at org.eclipse.swt.widgets.Widget.notifyListeners(Widget.java:1314)
  at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4082)
  at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3699)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$5.run(PartRenderingEngine.java:1150)
  at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:336)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1039)
  at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:153)
  at org.eclipse.ui.internal.Workbench.lambda$3(Workbench.java:680)
  at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:336)
  at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:594)
  at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:148)
  at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:151)
  at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
  at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:134)
  at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104)
  at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:388)
  at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:243)
  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
  at     sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessor   Impl.java:43)
  at java.lang.reflect.Method.invoke(Method.java:498)
  at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:653)
  at org.eclipse.equinox.launcher.Main.basicRun(Main.java:590)
  at org.eclipse.equinox.launcher.Main.run(Main.java:1499)
  </code></pre>
  
  <p>While the "Session Data" Reads:</p>
  
  <pre><code>    eclipse.buildId=4.7.3.M20180330-0640
      java.version=1.8.0_131
      java.vendor=Oracle Corporation
      BootLoader constants: OS=macosx, ARCH=x86_64, WS=cocoa, NL=en_IE
      Framework arguments:  -product     org.eclipse.epp.package.java.product   -    keyring     /Users/"name"/.eclipse_keyring
       Command-line arguments:  -os macosx -ws cocoa -arch x86_64 -    product     org.eclipse.epp.package.java.product -keyring      /Users/"name"/.eclipse_keyring
  
      This is a continuation of log file /Users/"name"/eclipse-          workspace/.metadata/.bak_0.log
     Created Time: 2020-04-12 20:31:14.758
  </code></pre>
  
  <p>As requested by Shai. I ran this command in terminal <code>":/usr/libexec/java_home -V"</code> which produced these results: </p>
  
  <blockquote>
    <p>Matching Java Virtual Machines (4): Matching Java Virtual Machines
    (4): 1.8.0_131, x86_64:   "Java SE 8"
    /Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home
    1.8.0_25, x86_64: "Java SE 8" /Library/Java/JavaVirtualMachines/jdk1.8.0_25.jdk/Contents/Home
    1.6.0_65-b14-462, x86_64: "Java SE 6" /Library/Java/JavaVirtualMachines/1.6.0_65-b14-462.jdk/Contents/Home
    1.6.0_65-b14-462, i386: "Java SE 6"   /Library/Java/JavaVirtualMachines/1.6.0_65-b14-462.jdk/Contents/Home
    –</p>
  </blockquote>