code: public int optInt( String key, int defaultValue ) {
        verifyIsNull();
        try{
           return getInt( key );
        }catch( Exception e ){
           return defaultValue;
        }
     }
docs: Get an optional int value associated with a key, or the default if there
  is no such key or if the value is not a number. If the value is a string,
  an attempt will be made to evaluate it as a number.
  
  @param key A key string.
  @param defaultValue The default.
  @return An object which is the value.