If, for put operations, you don't need the previous values existing in the cache/store then the following optimisation can be made:

cache.getAdvancedCache().withFlags(Flag.SKIP_CACHE_LOAD).put(key, value);

Note that in this case the value returned by cache.put is not reliable.
This optimisation skips a cache store read and can have very significant performance improvement effects.

More flags are described at Per-Invocation Flags