I use ControllerUtils.getCookie(String name) function to retrieve a cookie. Although the cookie is there, the function return null. With a debugger, I find the JForumExecutionContext.getRequest().getCookies() doesn't pick up all cookies. It only picks up 10 cookies while there are 12 cookie. I can't see any differences in domain nor path for cookies picked up by the function and cookies are not picked up by the function. How to make sure a cookie will be picked up by the function?

What are your cookies's name?
Are they all ASCII characters?

See this if they help:
http://www.velocityreviews.com/forums/t144469-with-request-getcookies-i-do-not-get-all-cookies.html
http://stackoverflow.com/questions/1969232/allowed-characters-in-cookies
http://www.ietf.org/rfc/rfc2965.txt

I write my cookie retrieval function and have the same result. So, the problem isn't related with the JForumExecutionContext.getRequest().getCookies().

I can retrieve the cookie right after it was created. I guess the problem likely relates with the cookie age.