public SessionId(byte[] sessionId){
  if (sessionId == null) {
    throw new NullPointerException("Session ID must not be null");
  }
  this.id=Arrays.copyOf(sessionId,sessionId.length);
}

public SessionId ( byte [ ] sessionId ) { if ( sessionId == null ) { throw new NullPointerException ( "Session ID must not be null" ) ; } this . id = Arrays . copyOf ( sessionId , sessionId . length ) ; }
creates a session identifier based on given bytes .
