docs: @Override
      protected Properties mergeProperties() throws IOException {
  
          Properties rslt = null;
  
          /*
           * If properties file encryption is used in this deployment, the
           * encryption key will be made available to the application as an
           * environment variable called UP_JASYPT_KEY.
           */
          final String encryptionKey = System.getenv(JAYSYPT_ENCRYPTION_KEY_VARIABLE);
          if (encryptionKey != null) {
  
              logger.info("Jasypt support for encrypted property values ENABLED");
  
              StandardPBEStringEncryptor encryptor = new StandardPBEStringEncryptor();
              encryptor.setPassword(encryptionKey);
              rslt = new EncryptableProperties(encryptor);
  
              /*
               * BEGIN copied from PropertiesLoaderSupport.mergeProperties()
               */
  
              if (this.localOverride) {
                  // Load properties from file upfront, to let local properties override.
                  loadProperties(rslt);
              }
  
              if (this.localProperties != null) {
                  for (int i = 0; i < this.localProperties.length; i++) {
                      CollectionUtils.mergePropertiesIntoMap(this.localProperties[i], rslt);
                  }
              }
  
              if (!this.localOverride) {
                  // Load properties from file afterwards, to let those properties override.
                  loadProperties(rslt);
              }
  
              /*
               * END copied from PropertiesLoaderSupport.mergeProperties()
               */
  
          } else {
  
              logger.info(
                      "Jasypt support for encrypted property values DISABLED;  "
                              + "specify environment variable {} to use this feature",
                      JAYSYPT_ENCRYPTION_KEY_VARIABLE);
  
              /*
               * The feature is not in use;  defer to the Spring-provided
               * implementation of this method.
               */
              return super.mergeProperties();
          }
  
          return rslt;
      }