Examples using glFeedbackBuffer?

Does anyone have any examples or demos using the new glFeedbackBuffer? I’m using the latest beta of JOGL which uses direct float buffers for feedback but I can’t seem to get it to work. Here’s what my code looks like, maybe you guys can help:

public void feedbackRender(GL gl){
        targets = net.java.games.jogl.util.BufferUtils.newFloatBuffer(4);
        gl.glFeedbackBuffer(4, GL.GL_3D, targets);
        gl.glRenderMode(GL.GL_FEEDBACK);
        gl.glBegin(GL.GL_POINTS);
        gl.glVertex3f(-700.0f,-300.0f,7500.0f);
        gl.glEnd();
        gl.glRenderMode(GL.GL_RENDER);
}
public void testReturn(){
        
        for(int i = 0; i<4; i++){
           System.out.println("target test["+i+"]: " +targets.get(i));
        }
}

The testReturn method is printing out all zeroes, any ideas?