mapResponse.put( "success", true );
mapResponse.put( "message", "Success message" );
mapResponse.put( "param1", param1 );
mapResponse.put( "param2", param2 );
XStream xstream = new XStream( new DomDriver() );
xstream.alias( "response", Map.class );
StringBuilder xmlBuilder = new StringBuilder();
xmlBuilder.append( "<?xml version=\"1.0\" encoding='UTF-8'?>" );
xmlBuilder.append( xstream.toXML( mapResponse ) );