you can also consider passing the char[] to the String constructor, and encrypting it.
here's a method to do the encryption for you.
Code:
        /**
    * Returns the encrypted password.
    * 
    * @param password 
    * @return The encrypted password.
    */
   public static final String encrypt(String password) {
      MessageDigest md;
      String encryptedPass = null;
      try {
         md = MessageDigest.getInstance("SHA");
         byte[] shaBytes = md.digest(password.
               getBytes("UTF-8" ));
         encryptedPass = new BigInteger(shaBytes).toString(16);
      } catch (NoSuchAlgorithmException e) {
         log.error(e);
      } catch (UnsupportedEncodingException e) {
         log.error(e);
      }
      
      return encryptedPass;
   }
Usage : encryptedPass = SomeClass.encrypt(new String(passwordField.getPassword());
please excuse the well off-topic post