code: public void put(String name, byte value) throws IllegalArgumentException {
          ObjectSlot slot = findMandatorySlot(name, byte.class);
          slot.fieldValue = Byte.valueOf(value);
          slot.defaulted = false; // No longer default value
      }
docs: Find and set the byte value of a given field named {@code name} in the
  receiver.
  
  @param name
  the name of the field to set.
  @param value
  new value for the field.
  
  @throws IllegalArgumentException
  if the corresponding field can not be found.