A cache can be defined as a component that transparently stores data so that future requests for that data can be served faster (no necessity to load from somewhere). If requested data is contained in the cache (cache hit), this request can be served by simply reading the cache, which is comparatively faster. Otherwise (cache miss), the data has to be recomputed or fetched from its original storage location, which is comparatively slower.
With Android, this term most times refers to the cache created and used by apps – which, when corrupted, might be the cause of "strange behavior" such as "unfortunately X has stopped" (see: force-close). In such cases it often helps to simply "clear" (empty) the cache of the app-in-question, which can be done in different ways:
- If your device is still usable, go to Settings › Apps, scroll to the app in question, open its page, and push the "clear cache" button.
- If those "force-closes" prevent you from performing the above, see How to clear Stock Browser cache when browser isn't installed? for some alternatives
- If none of the above works, a factory-reset includes emptying the cache. Take this as last-resort only, as it also removes all your data (see the factory-reset tag-wiki for details).