code: public static Properties mergeAndOverrideExisting(Properties props1, Properties props2) {
          Properties properties = new Properties();
          properties.putAll(props1);
          properties.putAll(props2);
          return properties;
      }
docs: Utility method to merge instructions from {@code props2} into the {@code props1}. The instructions
  from {@code props2} override the instructions  from {@code props1} (when both contain the same instruction)
  
  @param props1 the first set of instructions
  @param props2 the second set of instructions
  @return the new set of instructions containing the instructions from {@code props2} merged into {@code props1}.