open source alternatives to oracle coherence?

EhCache provides a decent replicated cache but has nowhere near the feature set Coherence provides.

JBoss Cache and EHCache are decent clustered cache solutions. But none of them have all the features and a nice admin console like Tangosol Oracle Coherence which is indeed the most advanced product in this category. For the price, there is a "Buy Now" button on the right of the Oracle Coherence web page.

Memcached is also an great open source alternative that is used by a lot of high-profile & high-traffic/volume apps.

Project Voldemort is great (free) alternative to coherence.

I have been watching for a good alternative also. The closest overall in features I have found are Terracotta and Redis but it would be helpful to know what aspects of Coherence are important to your project.