java convert string to Object?

I assume you mean that you want to convert the given string (stored inside a cookie) into an Employee domain object. First, I wouldn't do it the way that you're trying to do it. Instead, I would only store a session ID string inside the cookie, and then maintain a reference on the server that can take the client's session ID and retrieve an appropriate Employee object. You're storing and sending too much sensitive information in that cookie, and if you're using that cookie data for authorization purposes (i.e.: ismanager: false|true, user ID, etc.), then people can override that information and give themselves escalated privileges. Just store the Employee object as session data; it's already marked as Serializable, so take advantage of that and let the servlet container serialize/deserialize (freeze/thaw) the object for you so that whenever the user returns, said Employee object will be immediately available to your application code.
If you still want to store said string, you'll have to parse the comma-separated cookie string and manually construct/reconstruct a new Employee each time.

Thank you for your help!good luck for you