The case for HSQLDB as RDBMS for Java Development

HSQLD is a mature, high-performant database written in Java. It is used in several high profile popular commercial and open source products like Open Office 2.0 (Office productivity suite; competitor of MS Office), JBoss (Application Server), JFox (Application Server), Jonas (Application Server), Mathemetica, Hibernate (ORM), Jira (Defect Tracking), TrackStudio (Defect Tracking), C-JDBC (Database Clustering) etc.

It is a lightweight, embeddable database which eliminates the challenge of separate installation and configuration for the database component as with other databases like Oracle, SQL Server or MySQL.

The database is available as SQL scripts which makes it very easy to debug it, manually inspect and even modify the data.

It is tightly integrated with Java, making is very easy to use in Java applications. For example it supports Java stored procedures, functions and Triggers. 95% of JDBC interface is supported with full JDBC 2 DatabaseMetaData and ResultSetMetaData, batch statement and scrollable ResultSet functionality.

It supports standard SQL syntax which will make it easy for you to migrate to other databases down the road, should you want to. It supports disk tables upto 8GB and text tables upto 2GB which should be sufficient for most projects.

It can be used from applets, jar files, read-only media like CD, webstart and embedded applications. Did I mention that it is free and comes with source code?

I used it for several high-profile client projects with astounding success and highly recommend it. Two web application I developed for Invitrogen with HSQLDB as backend are:
EvoTrack Online - EvoTrack Online is a secure, online tool to track your custom antibody project. This is a complimentary service Invitrogen offers to all Custom Antibody customers.
EvoZone - EvoTrack Custom Library Services. EvoZone (internal name) is actually an application developer which allows rapid development of custom web based applications. It also can seamlessly integrate with external application and provides unified authentication & entitlements services from a central console.