code: public void disposeData(final int fromIndex, final int toIndex)
    {
      Arrays.fill(data, max(0, fromIndex), min(data.length, toIndex), (char) 0);
    }
docs: Wipes the data from memory, starting from the provided index,
  inclusive, and until the second index. Following recommendations
  from the <a href=
  "http://docs.oracle.com/javase/6/docs/technotes/guides/security/crypto/CryptoSpec.html#PBEEx">Java
  Cryptography Architecture (JCA) Reference Guide</a> Also wipes raw
  data.