Apache Derby goes in-memory
The Apache DB project has released Apache Derby 10.5.1.1. Derby is a pure Java relational database engine which can be run stand alone or embedded into a Java application. The 10.5.1.1 release sees the first appearance of an in-memory storage back end for the database.
This back end allows Derby to function as a memory based cache or high performance transient data store. It is also useful for developers who want to run unit tests on their database code without the performance penalties and persistence of disk based storage. It is a feature that has been requested for some time by users. The release sees improved support for SQL roles and generated columns and the ability to replicate encrypted databases.