Yes, though your object must be Serializable.
public void doGet(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {
// code here for real work: Assume obj is the object you want to send back
try {
ObjectOutputStream oos =
new ObjectOutputStream(res.getOutputStream());
oos.writeObject(obj);
oos.close();
} catch (IOException exc) {
exc.printStackTrace();
}
}