How to Improve the cache-header in java?
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I'm working with java-servlet-jsp. I used filter to store content on client's browser. 

    ((HttpServletResponse) response).setHeader("Cache-Control", sCache);
    ((HttpServletResponse) response).setHeader("Expires", new Date(_currentDate.getYear(), _currentDate.getMonth(), _currentDate.getDate() + 3).toString());

It store javascript, css, images with 3 day expiry. I'm using Yslow to test the speed of website. I want to know why primed cache doesn't shows that javascripts,css,images stored on client's browser. Check the image http://i.stack.imgur.com/mCAya.png . I tested Yslow on plus.google.com . They store image and when i check the graph it shows images in primed cache.

