public void setProperty(String key, String value) {
    if (null == value) {
      properties.remove(key);
    } else {
      properties.setProperty(key, value);
    }
  }
Sets a property on the configuration.

@param key
         the key (not {@code null}).
@param value
         the value, or {@code null} to remove it.
ambari-server/src/main/java/org/apache/ambari/server/configuration/Configuration.java