For my application i have used ehcache .. and for that everything is explained in detail here

The only problem i encountered was that it also cached my post request .. in order to exclude all my post request from being cached i overrode the methode caclulatekey to return null for post requests .. Am sure there is some configuration variable which one could set in the web.xml or ehcache.xml but i was to lazy to search ..

protected String calculateKey(HttpServletRequest httpRequest) {
        if (httpRequest.getMethod().equals("POST"))
            return null; ...

You could then use some custom tag for caching some parts of your page. for e.g seam has a tag you could also have a tag similar to that and cache your page fragments.