public ObjectId(byte[] b){
  if (b.length != 12)   throw new IllegalArgumentException("need 12 bytes");
  ByteBuffer bb=ByteBuffer.wrap(b);
  _time=bb.getInt();
  _machine=bb.getInt();
  _inc=bb.getInt();
  _new=false;
}

public ObjectId ( byte [ ] b ) { if ( b . length != 12 ) throw new IllegalArgumentException ( "need 12 bytes" ) ; ByteBuffer bb = ByteBuffer . wrap ( b ) ; _time = bb . getInt ( ) ; _machine = bb . getInt ( ) ; _inc = bb . getInt ( ) ; _new = false ; }
constructs an objectid given its 12 - byte binary representation .
