code: public final Object getObject(Key key)
          throws IOException, ClassNotFoundException, NoSuchAlgorithmException,
              InvalidKeyException
      {
          if (key == null) {
              throw new NullPointerException("key is null");
          }
  
          try {
              return unseal(key, null);
          } catch (NoSuchProviderException nspe) {
              // we've already caught NoSuchProviderException's and converted
              // them into NoSuchAlgorithmException's with details about
              // the failing algorithm
              throw new NoSuchAlgorithmException("algorithm not found");
          } catch (IllegalBlockSizeException ibse) {
              throw new InvalidKeyException(ibse.getMessage());
          } catch (BadPaddingException bpe) {
              throw new InvalidKeyException(bpe.getMessage());
          }
      }
docs: Retrieves the original (encapsulated) object.
  
  <p>This method creates a cipher for the algorithm that had been used in
  the sealing operation.
  If the default provider package provides an implementation of that
  algorithm, an instance of Cipher containing that implementation is used.
  If the algorithm is not available in the default package, other
  packages are searched.
  The Cipher object is initialized for decryption, using the given
  <code>key</code> and the parameters (if any) that had been used in the
  sealing operation.
  
  <p>The encapsulated object is unsealed and de-serialized, before it is
  returned.
  
  @param key the key used to unseal the object.
  
  @return the original object.
  
  @exception IOException if an error occurs during de-serialiazation.
  @exception ClassNotFoundException if an error occurs during
  de-serialiazation.
  @exception NoSuchAlgorithmException if the algorithm to unseal the
  object is not available.
  @exception InvalidKeyException if the given key cannot be used to unseal
  the object (e.g., it has the wrong algorithm).
  @exception NullPointerException if <code>key</code> is null.