code: public byte getByte(final String key) {
  		final String value = getProperty(key);
  		if (value == null) {
  			throw new NumberFormatException("Couldn't parse property to byte.");
  		}
  		return Byte.parseByte(value);
  	}
docs: Gets the prefixed key and parse it to an byte-value.
  
  @param key
  key value
  @return byte-representation of value