Hi Kesava,
By default, Liferay is using it's own cache, to render pages faster. You'll need to deactivate it in development environments.
I suggest you take a look at the file named "portal-developer.properties", located in the Liferay source (the real sources, not the ext or plugin projects).
Those caches work for Javascript, velocity, etc. We usually deactivate all of them in our development plateforms. To do so, just include "portal-developer.properties" in your portal-*.properties (usually not the portal-ext.properties, as you don't want to get ride of the caches in a production environement).
include-and-override=portal-developer.properties
If you only want the theme caches to be removed, just add the following lines in portal-ext.properties
theme.css.fast.load=false
theme.images.fast.load=false
Regards,
Alexandre FILLATRE
