code: public boolean set(boolean value)
      {
          String prevValue = setString(Boolean.toString(value));
          if (prevValue == null) {
              prevValue = getDefaultValue();
              if (prevValue == null) {
                  return false;
              }
          }
          return toBoolean(prevValue);
      }
docs: Sets the value of this boolean property.
  
  @return The previous value, or the default value if not set.