Tomcat 7 : request.getCookies() still returns a cookie that I deleted on the client

I'm running Tomcat 7.

I request localhost:8080 and using firebug I see a pre-existing cookie is being sent 开发者_StackOverflow中文版with the request.

I then delete the cookie manually on the client .

I reload the page. Firebug shows no cookie is sent with the request.

On the server however, request.getCookies() still sees the cookie that was sent with the initial request. I would like to avoid this.

If I then restart Tomcat, and then re-reload the page, request.getCookies() no longer finds the old cookie.

Why is this happening? How can I stop this happening?