code: public static String getUnqualifiedKey (String qualifiedKey)
      {
          if (!qualifiedKey.startsWith(QUAL_PREFIX)) {
              throw new IllegalArgumentException(
                  qualifiedKey + " is not a fully qualified message key.");
          }
  
          int qsidx = qualifiedKey.indexOf(QUAL_SEP);
          if (qsidx == -1) {
              throw new IllegalArgumentException(
                  qualifiedKey + " is not a valid fully qualified key.");
          }
  
          return qualifiedKey.substring(qsidx+1);
      }
docs: Returns the unqualified portion of the key from a fully qualified message key.
  
  @see #qualify