H2 is an embeddable RDBMS written in Java
Apache IoTDB
Relational database replication tool based on XML Schema
Database file mapping names to records, implementing a file-system
Heap organised database service (Java library)
elementary database files for Java, B+ tree index files, ISAM
Java library to remove Object/Relation Impedance
Java Based Heavy-duty utilitity to process large delimited text files