private static void checkNumericSystemProperty(String property, Range<Integer> validRange) {
    String value = System.getProperty(property);
    if (value == null) {
      return;
    }

    int parsed;
    try {
      parsed = Integer.parseInt(value);
    } catch (NumberFormatException ex) {
      throw new NumberFormatException(property + " must be an integer: " + value);
    }
    if (validRange.hasLowerBound() && validRange.lowerEndpoint() > parsed) {
      throw new NumberFormatException(
          property + " cannot be less than " + validRange.lowerEndpoint() + ": " + value);
    } else if (validRange.hasUpperBound() && validRange.upperEndpoint() < parsed) {
      throw new NumberFormatException(
          property + " cannot be greater than " + validRange.upperEndpoint() + ": " + value);
    }
  }
Gets whether or not to skip pushing tags to existing images. This is defined by the {@code
jib.skipExistingImages} system property.

@return {@code true} if Jib should skip pushing tags to existing images, {@code false} if not
jib-core/src/main/java/com/google/cloud/tools/jib/global/JibSystemProperties.java