public static int parsePort(String portOption) {
    if (portOption == null || portOption.equals("")) {
      return Integer.getInteger(TEST_OVERRIDE_DEFAULT_PORT_PROPERTY, DEFAULT_LOCATOR_PORT);
    } else {
      int result = Integer.parseInt(portOption);
      if (result < 1 || result > 65535) {
        throw new IllegalArgumentException(
            "The -port= argument must be greater than 0 and less than 65536.");
      } else {
        return result;
      }
    }
  }
Default file name for locator log: <code>"locator.log"</code>
geode-core/src/main/java/org/apache/geode/internal/DistributionLocator.java