If you enable caching but do not provide any special configuration for a servlet or JSP page, the default cache configuration is as follows:
The default cache timeout is 30 seconds.
Only the HTTP GET method is eligible for caching.
HTTP requests with cookies or sessions automatically disable caching.
No special consideration is given to Pragma:, Cache-control:, or Vary: headers.
The default key consists of the servlet path minus pathInfo and the query string.
A least-recently-used list is maintained to delete cache entries if the maximum cache size is exceeded.
Key generation concatenates the servlet path with key field values, if any are specified.