code: public <T> void remapField(Class<T> type, String fromJson, String toJava) {
  		JsonReaderI<T> map = this.getMapper(type);
  		if (!(map instanceof MapperRemapped)) {
  			map = new MapperRemapped<T>(map);
  			registerReader(type, map);
  		}
  		((MapperRemapped<T>) map).renameField(fromJson, toJava);
  	}
docs: remap field name in custom classes
  
  @param fromJson
  field name in json
  @param toJava
  field name in Java
  @since 2.1.1