private String getProperty(String key, String defaultValue) {
      if (configProperties.containsKey(key)) {
        return configProperties.get(key);
      }

      return defaultValue;
    }
Get the property value for the specified key. If not present, return default value.
@param key The key for which property value is required.
@param defaultValue Default value to return if key is not found.
@return
ambari-server/src/main/java/org/apache/ambari/server/agent/RecoveryConfigHelper.java