code: @SuppressWarnings("rawtypes")
  	public JsonWriterI getWriterByInterface(Class<?> clazz) {
  		for (WriterByInterface w : writerInterfaces) {
  			if (w._interface.isAssignableFrom(clazz))
  				return w._writer;
  		}
  		return null;
  	}
docs: try to find a Writer by Cheking implemented interface
  @param clazz class to serialize
  @return a Writer or null