code: String getProperty(String key) {
          String value = properties.get(key);
          if (value == null) {
              throw new RuntimeException("No property value found for key " + key);
          }
          return value;
      }
docs: Gets the value for the given key in the properties map. If the property is not found, an exception is thrown.
  
  @param key
  the key to look up value for
  @return value of the property
  @throws RuntimeException
  if the property is not found