How to create a simple distributed Map for Java application?

I am looking for a Map to share information between two instances of a Java web application running on separate machines. Reads and writes to this map need t开发者_运维知识库o be very fast and don't have to be transactional i.e. its ok if one instance has stale data for a while.

Any recommendations?

I need to keep track of the last time a user did something in the application, so its not terribly bad if this information is out of date. Speed and ease of use are important. I don't want writes to the Map to impact response times.

I would try Hazelcast, JGroups or Ehcache. All support a distributed map.

EDIT: Another option is to use RMI top a service running in one or the other JVM. This avoids the need for an additional library.

Additionally, there is Memcached which is very robust and proven over the time.