public int hashCode() {
    int result = major;
    result = 31 * result + minor;
    result = 31 * result + micro;
    result = 31 * result + ObjectUtil.hashCode(getQualifier());
    result = 31 * result + Boolean.hashCode(isSnapshot);
    return result;
  }
A version number with format major.minor.micro-qualifier.
spock-core/src/main/java/org/spockframework/util/VersionNumber.java