JetBrains Xodus is a transactional schema-less embedded database that is written in Java and Kotlin.
Xodus is transactional and fully ACID-compliant.
Xodus reads are highly concurrent. They 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.
Xodus is written in pure Java and Kotlin.
Xodus is free and licensed under Apache 2.0.