title: gwt: Cause of this Umbrella Exception?
body: <p>In my project i am using gwt and the libary gwt-connectors 2.4.. The following Code throws an NullPointer-Exception, and it would be great if someone can help me to find the reason for this exception! How can i solve that?</p>
  
  <pre><code>public class Projekt implements EntryPoint {
  
      private RootPanel rootPanel;
      Image img;
      Shape shapei;
      Connector con;
      Widget connected;
       Image logo;
       Image logo2;
  
  
      public void onModuleLoad() {
  
          rootPanel = RootPanel.get("gwtContainer");
          rootPanel.setSize("1902", "868");
  
           final AbsolutePanel boundaryPanel = new AbsolutePanel();
           boundaryPanel.setStyleName("frame1");
           boundaryPanel.setSize("1455px", "600px");       
  
           final Diagram diagram = new Diagram(boundaryPanel);
  
           RootPanel.get().add(boundaryPanel, 446, 242);
  
           Button la = new Button("Push");
           la.setSize("200", "200");
           boundaryPanel.add(la);
  
           Button la2 = new Button("Push2");
           la2.setSize("200", "200");
           boundaryPanel.add(la2);
  
           Image img2 = new Image("images/variable.svg");
           img2.setSize("200", "200");
           boundaryPanel.add(img2, 200,200);
  
           final Shape shapei2 = new Shape(img2);
           shapei2.showOnDiagram(diagram);
  
           la.addClickHandler(new ClickHandler(){
  
              @Override
              public void onClick(ClickEvent event) {
                   img = new Image("images/concrete.svg");
                   img.setSize("200", "200");
                   boundaryPanel.add(img, 200,200);
  
  
                   boundaryPanel.add(img, 100,100);
                    Shape shapei = new Shape(img);
                   shapei.showOnDiagram(diagram);
  
              }}
  
           );
           la2.addClickHandler(new ClickHandler(){
  
                  @Override
                  public void onClick(ClickEvent event) {
                      con = new Connector(100, 300, 300, 500);
                       con.showOnDiagram(diagram);
                  }
  
               });
           diagram.addDiagramListener(new DiagramListener(){
           public void onElementConnect(ElementConnectEvent event) {
               if (con.startEndPoint.isGluedToConnectionPoint()) {
                  connected = con.startEndPoint.gluedConnectionPoint.parentWidget;
                   if(connected.equals(shapei.connectedWidget)){//line 97, think here is the problem
                 logo = new Image("images/xor.svg");
                 logo.setSize("100", "100");
                 boundaryPanel.add(logo);
               }
                   else if(connected.equals(shapei2.connectedWidget)){ 
                        logo2 = new Image("images/and.svg");
                     logo2.setSize("100", "100");
                     boundaryPanel.add(logo2);
                   };
             }}
  
          @Override
          public void onConnectorClick(ConnectorClickEvent event) {
              // TODO Auto-generated method stub
  
          }
  
          @Override
          public void onConnectorDoubleClick(ConnectorDoubleClickEvent event) {
              // TODO Auto-generated method stub
  
          }
  
          @Override
          public void onDiagramAdd(DiagramAddEvent event) {
              // TODO Auto-generated method stub
  
          }
  
          @Override
          public void onDiagramRemove(DiagramRemoveEvent event) {
              // TODO Auto-generated method stub
  
          }
  
          @Override
          public void onElementDrag(ElementDragEvent event) {
              // TODO Auto-generated method stub
  
          }
  
  
  
  
  });
           }}
  </code></pre>
  
  <p>and this is log:</p>
  
  <pre><code>09:11:25.249 [ERROR] [projekt] Uncaught exception escaped
  com.google.gwt.event.shared.UmbrellaException: Exception caught: null
      at com.google.gwt.event.shared.HandlerManager.fireEvent(HandlerManager.java:129)
      at com.google.gwt.user.client.ui.Widget.fireEvent(Widget.java:129)
      at com.google.gwt.event.dom.client.DomEvent.fireNativeEvent(DomEvent.java:116)
      at com.google.gwt.user.client.ui.Widget.onBrowserEvent(Widget.java:177)
      at com.google.gwt.user.client.DOM.dispatchEventImpl(DOM.java:1351)
      at com.google.gwt.user.client.DOM.dispatchEvent(DOM.java:1307)
      at sun.reflect.GeneratedMethodAccessor43.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
      at java.lang.reflect.Method.invoke(Method.java:498)
      at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
      at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
      at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
      at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:338)
      at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:219)
      at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:136)
      at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:571)
      at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:279)
      at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91)
      at com.google.gwt.core.client.impl.Impl.apply(Impl.java)
      at com.google.gwt.core.client.impl.Impl.entry0(Impl.java:242)
      at sun.reflect.GeneratedMethodAccessor40.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
      at java.lang.reflect.Method.invoke(Method.java:498)
      at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
      at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
      at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
      at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:293)
      at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:547)
      at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:364)
      at java.lang.Thread.run(Thread.java:745)
  Caused by: java.lang.NullPointerException: null
      at com.exa.projekt.client.Projekt$3.onElementConnect(Projekt.java:97)
      at pl.tecna.gwt.connectors.client.Diagram.onElementConnect(Diagram.java:421)
      at pl.tecna.gwt.connectors.client.elements.EndPoint.glueToConnectionPoint(EndPoint.java:71)
      at pl.tecna.gwt.connectors.client.drop.DiagramWidgetDropController.onDrop(DiagramWidgetDropController.java:57)
      at com.allen_sauer.gwt.dnd.client.PickupDragController.dragEnd(PickupDragController.java:130)
      at com.allen_sauer.gwt.dnd.client.MouseDragHandler.drop(MouseDragHandler.java:529)
      at com.allen_sauer.gwt.dnd.client.MouseDragHandler.onMouseUp(MouseDragHandler.java:277)
      at com.google.gwt.event.dom.client.MouseUpEvent.dispatch(MouseUpEvent.java:56)
      at com.google.gwt.event.dom.client.MouseUpEvent.dispatch(MouseUpEvent.java:1)
      at com.google.gwt.event.shared.GwtEvent.dispatch(GwtEvent.java:1)
      at com.google.web.bindery.event.shared.EventBus.dispatchEvent(EventBus.java:40)
      at com.google.web.bindery.event.shared.SimpleEventBus.doFire(SimpleEventBus.java:193)
      at com.google.web.bindery.event.shared.SimpleEventBus.fireEvent(SimpleEventBus.java:88)
      at com.google.gwt.event.shared.HandlerManager.fireEvent(HandlerManager.java:127)
      at com.google.gwt.user.client.ui.Widget.fireEvent(Widget.java:129)
      at com.google.gwt.event.dom.client.DomEvent.fireNativeEvent(DomEvent.java:116)
      at com.google.gwt.user.client.ui.Widget.onBrowserEvent(Widget.java:177)
      at com.google.gwt.user.client.DOM.dispatchEventImpl(DOM.java:1351)
      at com.google.gwt.user.client.DOM.dispatchEvent(DOM.java:1307)
      at sun.reflect.GeneratedMethodAccessor43.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
      at java.lang.reflect.Method.invoke(Method.java:498)
      at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
      at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
      at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
      at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:338)
      at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:219)
      at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:136)
      at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:571)
      at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:279)
      at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91)
      at com.google.gwt.core.client.impl.Impl.apply(Impl.java)
      at com.google.gwt.core.client.impl.Impl.entry0(Impl.java:242)
      at sun.reflect.GeneratedMethodAccessor40.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
      at java.lang.reflect.Method.invoke(Method.java:498)
      at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
      at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
      at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
      at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:293)
      at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:547)
      at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:364)
      at java.lang.Thread.run(Thread.java:745)
  </code></pre>