java.lang.NoClassDefFoundError: org/eclipse/draw2d/LightweightSystem

Question

I am building a Eclipse plug-in project with The Eclipse Graphical Editing Framework (GEF). It's ok that I write a single class for testing with example code I find on the internet, the code is following:

public class Test {
    public static void main(String args[]){
        Shell shell = new Shell(); 
        shell.open();
        Display display = shell.getDisplay();
        LightweightSystem lws = new LightweightSystem(shell);
        IFigure panel = new Figure();
        lws.setContents(panel);
        RectangleFigure node1 = new RectangleFigure();
        RectangleFigure node2 = new RectangleFigure();
        node1.setBackgroundColor(ColorConstants.red);
        node1.setBounds(new Rectangle(30, 30, 64, 36));
        node2.setBackgroundColor(ColorConstants.blue);
        node2.setBounds(new Rectangle(300, 300, 64, 36));
        PolylineConnection conn = new PolylineConnection();
        conn.setSourceAnchor(new ChopboxAnchor(node1));
        conn.setTargetAnchor(new ChopboxAnchor(node2));
        conn.setTargetDecoration(new PolygonDecoration());
        Label label = new Label("Midpoint");
        label.setOpaque(true);
        label.setBackgroundColor(ColorConstants.buttonLightest);
        label.setBorder(new LineBorder());
        conn.add(label, new MidpointLocator(conn, 0));
        panel.add(node1);
        panel.add(node2);
        panel.add(conn);
        while (!shell.isDisposed ()) { 
            if (!display.readAndDispatch ()) 
               display.sleep (); 
        }
    }//main
}

It works.

But - when I try to build figures in a EditorPart (org.eclipse.ui.IEditorPart) instance class, it turns bad and giving me the following error code:

**org.eclipse.e4.core.di.InjectionException: java.lang.NoClassDefFoundError:** org/eclipse/draw2d/LightweightSystem

It's quite strange because I just write 3 lines at the editor's createPartControl method:

Shell shell = parent.getShell();
Display display = shell.getDisplay();
LightweightSystem lws = new LightweightSystem(shell);

So any body help?

Answer 1

Are your dependencies set properly? You need to add org.eclipse.draw2d for the LightweightSystem.