// The message can't be sent back to the browser if the getWriter method has already been called.
// So use the output stream from the response and convert to a writer.
Writer responseWriter = new OutputStreamWriter( response.getOutputStream() );
GeoJsonWriter featureWriter = new GeoJsonWriter( responseWriter );
featureWriter.feature();
featureWriter.key( "properties" );
featureWriter.value( (Object)null );
featureWriter.key( "geometry" );
featureWriter.value( (Object)null );
featureWriter.key( "bbox" );