@Override
    public int getPrimaryDisplay() {
        // TODO Auto-generated method stub
        return 0;
    }
This is called: 1) When the context thread starts 2) Any time the canvas becomes displayable
again. In the first call of this method, OpenGL context is not ready yet. Therefore, OpenCL
context cannot be created. The second call of this method is done after "simpleInitApp" is
called. Therefore, OpenCL won't be available in "simpleInitApp" if Canvas/Swing is used. To use
OpenCL with Canvas/Swing, you need to use OpenCL in the rendering loop "simpleUpdate" and check
for "context.getOpenCLContext()!=null".
jme3-lwjgl/src/main/java/com/jme3/system/lwjgl/LwjglCanvas.java