code: private String toQualifierString() {
  
      Qualifier qualifier = getQualifier();
  
      int qualifierNumber = getQualifierNumber();
  
      return (qualifier.isUndefined() ? StringUtils.EMPTY_STRING
        : (qualifierNumber > 0 ? String.format(".%s%d", qualifier.getAbbreviation(), qualifierNumber)
          : String.format(".%s", qualifier.name())));
    }
docs: Returns a {@link String} containing the version {@link Qualifier} and qualifier number of this {@link Version}.
  
  @return a {@link String} containing the {@link Version.Qualifier} and qualifier number, or an empty {@link String}
  if the {@link Version.Qualifier} is undefined.
  @see #getQualifierNumber()
  @see #getQualifier()