Here the blog explains how HBase and Hazelcast can be integrated: http://blog.codepoly.com/distribute-with-hazelcast-persist-into-hbase
The point is you store some of the data in Hazelcast (the most recent or frequently used ones), namely use Hazelcast as cache. See eviction options: http://www.hazelcast.com/docs/2.5/manual/single_html/#MapEviction
After integrating HBase, each get() will load record from HBase into Hazelcast.