code: public synchronized String findValue(String k) {
          if (k == null) {
              for (int i = nkeys; --i >= 0;)
                  if (keys[i] == null)
                      return values[i];
          } else
              for (int i = nkeys; --i >= 0;) {
                  if (k.equalsIgnoreCase(keys[i]))
                      return values[i];
              }
          return null;
      }
docs: Find the value that corresponds to this key.
  It finds only the first occurrence of the key.
  @param k the key to find.
  @return null if not found.