Databases

Apache Derby
Apache Derby, an Apache DB subproject, is an open source relational database implemented entirely in Java and available under the relational database implemented entirely in Java and available under the Apache License, Version 2.0. Some key advantages include: * Derby has a small footprint -- about 2 megabytes for the base * Derby has a small footprint -- about 2 megabytes for the base engine and embedded JDBC driver. * Derby is based on the Java, JDBC, and SQL standards. * Derby provides an embedded JDBC driver that lets you embed Derby in any Java-based solution. * Derby also supports the more familiar client/server mode with the Derby Network Client JDBC driver and Derby Network Server. * Derby is easy to install, deploy, and use.

Berkeley Derby Java Edition
Berkeley DB JE is a high performance, transactional storage engine written entirely in Java. Like the highly successful Berkeley DB engine written entirely in Java. Like the highly successful Berkeley DB product, Berkeley DB JE executes in the address space of the application, without the overhead of client/server communication. It stores data in the applications native format, so no runtime data translation is required. Berkeley DB JE supports full ACID transactions and recovery. It provides an easy-to-use interface, allowing programmers to store and retrieve information quickly, simply and reliably. Berkeley DB JE was designed from the ground up in Java. It takes full advantage of the Java environment. The Berkeley DB JE API provides a Java Collections-style interface, as well as a programmatic interface similar to the Berkeley DB API. The architecture of Berkeley DB JE supports high performance and concurrency for both read-intensive and write-intensive workloads. Berkeley DB JE is different from all other Java databases available today. Berkeley DB JE is not a relational engine built in Java. It is a Berkeley DB-style embedded store, with an interface designed for programmers, not DBAs. Berkeley DB JEs architecture employs a log-based, no-overwrite storage system, enabling high concurrency and speed while providing ACID transactions and record-level locking. Berkeley DB JE efficiently caches most commonly used data in memory, without exceeding application-specified limits. In this way Berkeley DB JE works with an application to use available JVM resources while providing access to very large data sets.

Hypersonic SQL
hsqldb is a relational database engine written in Java, with a JDBC driver, supporting a rich subset of ANSI-92 SQL (BNF tree format). JDBC driver, supporting a rich subset of ANSI-92 SQL (BNF tree format). It offers a small (less than 160k), fast database engine which offers both in memory and disk based tables. Embedded and server modes are available. Additionally, it includes tools such as a minimal web server, in-memory query and management tools (can be run as applets) and a number of demonstration examples.

Axion
Axion is a small, fast, open source relational database system (RDBMS) supporting SQL and JDBC written in and for the Java programming (RDBMS) supporting SQL and JDBC written in and for the Java programming language.

db4o
db4o (database for objects) is the open source object database for Java. Features include: fast native Java object persistence, ACID for Java. Features include: fast native Java object persistence, ACID transactions, query-by-example, S.O.D.A. object query API, automatic class schema recognition, small footprint.

Ozone DB
The Ozone Database Project is a open initiative for the creation of an open source, Java based, object-oriented database management of an open source, Java based, object-oriented database management system. Ozone includes a fully W3C compliant DOM implementation that allows you to store XML data. You can use any XML tool to provide and access these data. Support classes for Apache Xerces-J and Xalan-J are included.

NeoDatis ODB
NeoDatis ODB is a new generation Object Oriented Database. ODB is a real transparent persistence layer that allows anyone to persist a real transparent persistence layer that allows anyone to persist native objects with a single line of code. ODB can be used as an embedded database engine that can be seamlessly integrated to any product as an embedded database or in client/server mode.

Mckoi DQL Database
Mckoi SQL Database is optimized to run as a client/server database server for multiple clients, however it can also be embedded in database server for multiple clients, however it can also be embedded in an application as a stand-alone database. It is highly multi-threaded and features an extendable object-oriented engine.

Perst
Perst is an object-oriented embedded database for Java and .NET applications that need to deal with persistent data. It is easy to use applications that need to deal with persistent data. It is easy to use and provides high performance. Although Perst is very simple, it provides fault-tolerant support (ACID transactions) and concurrent access to the database. The main advantage of Perst is its tight integration with programming languages.

Ashpool
Ashpool is a lightweight XML Database written in Java(tm). Its goal is to use standard SQL92 syntax to query, add, update, and delete goal is to use standard SQL92 syntax to query, add, update, and delete XML documents via a JDBC driver. The XML documents must hold to a table like structure. The reason for the table structure restriction is that SQL was designed to query table data not hierarchical data.

One$DB
One$DB is a version of Daffodil DB , a J2EE-certified, JDBC 3.0 and SQL-99 compliant Java database. It is available in both Network and and SQL-99 compliant Java database. It is available in both Network and Embedded editions and has been designed to handle complex computing environments that demand a robust, scalable and feature-rich RDBMS that can operate across platforms.

Neo4j
Neo4j is a graph database. It is an embedded, disk-based, fully transactional Java persistence engine that stores data structured in transactional Java persistence engine that stores data structured in graphs rather than in tables. A graph (mathematical lingo for a network) is a flexible data structure that allows a more agile and rapid style of development.

SmallSQL Database
SmallSQL is a 100% pure Java DBMS, a relational database for Java desktop applications. It has a JDBC 3.0 interface and offering many ANSI desktop applications. It has a JDBC 3.0 interface and offering many ANSI SQL 92 and ANSI SQL 99 features. It is very small and fast because it does not have a network interface.

Jalisto
Jalisto is a lightweight transactional database written entirely in Java. Jalisto comes in two versions: Jalisto SE (Standard Edition) in Java. Jalisto comes in two versions: Jalisto SE (Standard Edition) and Jalisto ME (Micro Edition). Jalisto SE is an ideal solution for embedded and stand-alone systems. Jalisto ME, which will be available in Q4, targets mobile environments including cell phones, PDAs, and is compatible with the Java 2 Platform Micro Edition (J2ME).

Quadcap Embeddable Database
QED, the Quadcap Embeddable Database. QED is a fast, small, pure Java, relational database, implementing the SQL 92 standard, with Java, relational database, implementing the SQL 92 standard, with transactions and resilient failure recovery. QED has a novel open source license permitting free use of QED by all and free redistribution in other open source projects.

TinySQL
A very lightweight 100% Java text SQL engine that includes a JDBC driver driver

Excel JDBC Driver
JDBC Driver for the spreadsheets Excel, StarOffice and OpenOffice. Turn a directory with spreadsheets into a database. xls OpenOffice. Turn a directory with spreadsheets into a database. xls filenames become database schemas, sheets become tables. Use a rich subset of SQL to create sheets and query sheets. Join sheets, query database data and store it into excel or fill database tables with spreadsheets.

MyOODB
MyOODB (My Object-Oriented Database) is an integrated database and Web environment that provides true distributed objects, and Web environment that provides true distributed objects, implicit/explicit multi-concurrent nested transactions, seamless Web tunneling, and database self-healing. MyOODB is one part of a two part SDK solution. Together with MyOOWEB, MyOOSDK provides a development environment for people who desire small, fast, but powerful applications.

Metanotion Block File
A 100% pure Java, lightweight, single file embeddable database. Functionally similar to a cross between SQLite and BerkeleyDB. Developed Functionally similar to a cross between SQLite and BerkeleyDB. Developed for use with PDA and Mobile applications.

JODB
JODB (Java Objects Database) is an open source object-oriented database. The database uses a cache based on Soft References to avoid database. The database uses a cache based on Soft References to avoid using too much memory when the application requires it. The queries are optimized to use the minimal possible object instantiations during the search to avoid excessive garbage collection.

YaRDBMS
The yaRDBMS (yet another relational database management system) is a Java based, transactional highly concurrent relational database is a Java based, transactional highly concurrent relational database management system with advanced query optimization, indexing features and crash recovery.

jiql
jiql is a Java database for Cloud computing. The database is accessed via a jdbc client. The data is actually stored in a cloud-based accessed via a jdbc client. The data is actually stored in a cloud-based data store, such as Googles BigTable. The fact is Google App Engine at present only supports python. Java programmers need not be excluded, as jiql provides a way to at least utilize Googles BigTable. By uploading the jiql python controller (jiql.py) to Google App Engine (GAE), the jiql.py acts as a gateway between the jiql database engine and Googles BigTable (GBT). So a Java application, using standard JDBC calls to the jiql JDBC client, is able to store critical data in GBT. As the DataStore sits in the cloud, you essentially have a solution for distributed database access. Thus, although you may not be able to host a JAVA program on GAE, you can still use the Data Store, which is probably the most important aspect of cloud-computing - that is scalability and high availability.