Spring integrates Memcached in three ways

There are currently 3 types of Memcached Client: 
Memcached Client for  Java 
SpyMemcached 
XMemcached

There have been various controversies among these three clients: 
Memcached Client for Java is more stable, earlier and wider than SpyMemcached; 
SpyMemcached is more efficient than Memcached Client for Java; 
XMemcached has better concurrency than SpyMemcache.

http://blog.csdn.net/u013725455/article/details/52102170