code: protected static String verifyNonEmpty(String value, String argName) {
          if (value != null) {
              value = value.trim();
              if (value.isEmpty()) {
                  value = null;
              }
          }
          if (value == null) {
              throw new IllegalArgumentException(argName);
          }
          return value;
      }
docs: Verifies a value is null or empty. Returns the value if non-empty and throws exception if empty.
  @param value the value to verify.
  @param argName the name of the value.
  @return Returns the value if non-empty.