Sun Microsystems has always been dismissive of IBM's open-source initiatives. But finding itself in need of a database to add to its Java Enterprise System software lineup, Sun has swallowed its pride and said it will adopt an open-source database with IBM roots.

Sun last week said it will offer Derby, a lightweight Java relational database, to Java developers to embed in applications so they can capture data and keep it readily accessible without relying on an outside database. Key parts of the Java Enterprise System, such as Directory Server and Identity Manager, would benefit from an embedded database.

Sun will get Derby from the Apache Software Foundation, but it's based on the Cloudscape database, which IBM donated to the foundation for open-source use. IBM acquired Cloudscape in 2001 when it bought Informix Software.

Sun's move isn't as surprising as it appears. The company has supported Derby's development alongside IBM as an Apache open-source project, and it counts 30 contributors to Derby from within its developer ranks. Derby "is a great fit for Java developers," says John Loiacono, Sun's senior VP for software. Sun is making all elements of the Java Enterprise System available as open-source software.