Open Source Java Database Engines/Servers

Firebird RDBMS offers ANSI SQL features & runs on Linux, Windows & several Unix platforms. Features excellent concurrency & performance & powerful stored procedure & trigger language. More information and downloads at https://firebirdsql.org/, issue tracker is https://github.com/FirebirdSQL/firebird/issues

Mondrian is an OLAP (online analytical processing) engine written in Java. It reads from JDBC data sources, aggregates data in a memory cache, and implements the MDX language and the olap4j and XML/A APIs.

HSQLDB is a relational database engine written in Java, with a JDBC driver, conforming to ANSI SQL:2023. A small, fast, multithreaded engine and server with memory and disk tables, LOBs, transaction isolation, multiversion concurrency and ACID.

The Lemur Project develops search engines, browser toolbars, text analysis tools, and data resources that support research and development of information retrieval and text mining software, including the Indri search engine in C++, the Galago search engine research framework in Java, the RankLib learning to rank library, ClueWeb09 and ClueWeb12 datasets and the Sifaka data mining application.

Blazegraph has moved to Github. Please see https://github.com/blazegraph/database/.

The BSBM (Berlin SPARQL Benchmark) suite for benchmarking RDF stores or RDB-2-RDF wrappers over the SPARQL protocol. Pure RDBMS benchmarking via SQL is also possible. Visit http://www4.wiwiss.fu-berlin.de/bizer/BerlinSPARQLBenchmark for more details.

OpenVista(R) is the open-source version of VistA, an enterprise grade health care information system developed by the U.S. Veterans Affairs and deployed at 1,500 global facilities. OpenVista is a registered trademark of Medsphere Systems Corporation

Ozone is a fully featured, object-oriented database management system implemented in Java and distributed under the LGPL open source license. The ozone project aims to evolve a database system that allows developers to build pure object-oriented systems.

This is a Java based xBase engine to read write and update dbf files. Using the package's classes and methods programmers can process dBase III and IV files and some clones (e.g. Clipper/FoxPro) along with index and tag files and the individual fiel

olap4j is an open Java API for connecting to OLAP servers and writing analytic applications. Code is at https://github.com/olap4j/olap4j.

Mirror of: https://github.com/osdldbt/ This Database Test Suite aims to create database workload test kits used to simulate heavy user loads for OLTP, Decision Support, and e-commerce database transactions. These test kits can also be used to gather performance results for Linux and other

SiebenGeisslein is a platform for orthogonal persistent applications. Its main components are an object store, an application server and an IDE. The features include multi-user support, crash-recovery, hot-deployments and transparent object evolution.

db4o is the world's leading open source object database for Java and .NET. Leverage fast native object persistence, ACID transactions, query-by-example, S.O.D.A object query API, automatic class schema evolution, small size (http://developer.db4o.com)

Egothor is a high-performance, full-featured text search engine written entirely in Java. It is a technology suitable for nearly any application that requires full-text search.

Conductor is an open-source, durable workflow orchestration engine designed to manage distributed systems, microservices, and AI-driven applications at internet scale. Originally built at Netflix and actively maintained by Orkes and the open-source community, Conductor simplifies complex workflow management by handling retries, failures, state persistence, and long-running process execution automatically. The platform enables developers to orchestrate AI agents, APIs, human approvals, and microservices using flexible JSON-based workflows with dynamic runtime execution. Conductor supports durable execution, deterministic orchestration, workflow replayability, and horizontal scalability, making it suitable for enterprise-grade applications and mission-critical automation. It offers polyglot worker support across languages such as Java, Python, JavaScript, Go, C#, Ruby, and Rust, allowing teams to integrate workflows into virtually any technology stack.

OpenRefine is a powerful Java-based tool designed to work with messy data and improve it. With OpenRefine you can load data, understand it, clean it up, transform it, reconcile it, and augment it with web services and external data. It allows you to do this all from a web browser and in the convenience and privacy of your own computer. OpenRefine keeps all data securely in your computer by running a small server on it, using your web browser to interact with it. When you're ready, then that is the only time the data will be shared outside of your computer. OpenRefine is available in over 15 languages, is cross-platform and part of the Code for Science & Society.

The iSeries Toolkit. Utilities that support Dynamic SQL, Messaging, IFS file access, User spaces, User indexes, Dynamic Native File Access, XML, and Source Generation. These RPGIV ILE and Java tools work on most recent releases of the iSeries and AS/400 p

Teiid is Enterprise Information Integration system. Teiid can virtualize and integrate data from multiple disparate information sources and provide as single Virtual DB

Java CSV is a small fast open source Java library for reading and writing CSV and plain delimited text files. All kinds of CSV files can be handled, text qualified, Excel formatted, etc.

Mayfly is an in-memory SQL implementation for unit testing. It is fast on small data sets and you can create or destroy a database as easily any other Java object.

Moved to https://github.com/DANS-KNAW/dans-dbf-lib.

Mnemosyne is an in-memory object database for Java. It uses AOP to achieve transparent persistence, and object level versioning and locking to provide ACID transaction support. Data is persisted through transaction logging and periodic system snapshots

The Eigenbase Project is an open-source platform for building advanced data management systems, and is backed by a non-profit organization which designs, develops, and promotes it.

The Malete database core is the new basis of OpenIsis, which has its roots in the UNESCO CDS/ISIS database. Traditionaly used in libraries; now a general purpose highspeed database.

Kneobase is an enterprise search engine, based upon the Lucene search engine and the Spring framework. It allows to perform full-text search across many different content sources. It is highly adaptable out-of-the-box and has a pluggable architecture.