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Java Caching System
JCS is a distributed caching system written in java for server-side java applications. It is intended to speed up dynamic web applications by providing a means to manage cached data of various dynamic natures. Like any caching system, the JCS is most useful for high read, low put applications 

License Apache Software License 
HomePage http://jakarta.apache.org/turbine/jcs/

OSCache
OSCache is a widely used, high performance J2EE caching framework. In addition to it’s servlet-specific features, OSCache can be used as a generic caching solution for any Java application. 

License Apache Software License 
HomePage http://www.opensymphony.com/oscache/

 

EHCache
EHCache is a pure Java, in-process cache with the following features: Fast,Simple, Acts as a pluggable cache for Hibernate 2.1., with Small foot print, Minimal dependencies, Fully documented and Production tested 

License Apache Software License 
HomePage http://ehcache.sourceforge.net/

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