MessageDigest update/digest method

Hi everyone!
I'd like to know if there's a way to invert operations of update/digest methods.
See the code belove:
byte b[] = ...;
byte d[];
MessageDigest md;
          try {
               md = MessageDigest.getInstance ("MD5");
          } catch (NoSuchAlgorithmException a) {
               md = null;
               md.update (b, 0, 7);
               d = md.digest ();
.....Having d byte array, can I obtain original array b from which I started.
Thank you very much all in advance
Diego

thank you

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