code: public static Long getTimeStampToleranceSystemProperty() {
          String timestampToleranceAsString = System.getProperty(ServletConstants.TIMESTAMP_TOLERANCE_SYSTEM_PROPERTY);
          if (timestampToleranceAsString != null && !timestampToleranceAsString.trim().equals("")) {
              try {
                  return Long.parseLong(timestampToleranceAsString);
              } catch (NumberFormatException ex) {
                  throw new IllegalArgumentException("Could not parse provided value as long: " + timestampToleranceAsString);
              }
          } else {
              return null;
          }
      }
docs: Returns the value of the {@link ServletConstants#TIMESTAMP_TOLERANCE_SYSTEM_PROPERTY} JVM system property as a {@link Long},
  or returns null if the property is empty.
  @return value of the {@link ServletConstants#TIMESTAMP_TOLERANCE_SYSTEM_PROPERTY} system property as a {@link Long}, or null if the property is empty.
  @throws IllegalArgumentException if the system property is present but not parseable as a Long.