Lightweight Java Object cache API [closed]

EHCache is very nice. You can create an in memory cache. Check out their code samples for an example of creating an in memory cache. You can specify a max size, and a time to live.

EHCache does offer some advanced features, but if your not interested in using them - don't. But it's nice to know they are there if your requirements ever change.

Here is an in memory cache. Created in code, with no configuration files.

CacheManager cacheManager = CacheManager.getInstance();int oneDay = 24 * 60 * 60;Cache memoryOnlyCache = new Cache("name", 200, false, false, oneDay, oneDay);cacheManager.addCache(memoryOnlyCache);

Creates a cache that will hold 200 elements, and has a ttl of 24 hours.

I really like the MapMaker that comes with Google Guava (API)

The JavaDoc has a pretty neat example that demonstrates both its ease of use and its power:

ConcurrentMap<Key, Graph> graphs = new MapMaker()   .concurrencyLevel(32)   .softKeys()   .weakValues()   .expiration(30, TimeUnit.MINUTES)   .makeComputingMap(       new Function<Key, Graph>() {         public Graph apply(Key key) {           return createExpensiveGraph(key);         }       });

Furthermore, release 10.0 of Guava introduced the much more extensive com.google.common.cache package (there's a nice wiki entry on how to use them).

You can also check out my little cache library called KittyCache at:

https://github.com/treeder/kitty-cache

There are some performance benchmarks vs ehcache.

It's used in the SimpleJPA project as a second level cache.