In Firefox, you clean the cache by selecting the Tools option in the browser (at the top of the page). Then select Clear Private Data. Cache is one of the items. Hit the Clear Private Data Now and your cache will be cleared.
In Internet Explorer, select the Tools option in the browser. Then select Internet Options. On the "General" tab look for the Browsing History section. Click on the Delete button. This will clear the cache.
For Java, go to your Start menu for Windows. Then select the Control Panel. When the items appear, select the Java item. In the "General" tab you'll have a Temporary Internet Files section. Select the Settings button and select Delete Files. Go ahead and delete items.
Start with clearing the cache in the browser first before trying to do the Java cache. You can also increase your cache size on your browser. Go to Tools > Options > Advanced and then select the Network tab. You'll see a cache size field. You can increase that to a larger size. Try doubling it and see if that clears your cache problem.