Xodus

JetBrains Xodus is a transactional schema-less embedded database that is written in Java and Kotlin. It was initially developed for JetBrains YouTrack, an issue tracking and project management tool. Xodus is also used in JetBrains Hub, the user management platform for JetBrains' team tools, and in some internal JetBrains projects. Xodus is highly concurrent. Reads are completely non-blocking due to MVCC and true snapshot isolation. Xodus is schema-less and agile. It does not require schema migrations or refactorings. Xodus is embedded. It does not require installation or administration. There are three different ways to deal with data, which results in three different API layers: Environments, Entity Stores and Virtual File Systems. Gradle is used to build, test, and publish. JDK 1.8 or higher is required.