In seeking to keep Java standardized, Sun Microsystems has turned to an open source project led by Oracle for its standard for mapping software objects into relational databases.

The process of mapping is a key one to Java programmers because objects are not easily translated into relational data, the way transactions are. Instead, they must be mapped into a table of rows and columns so that both the functionality of the object and its data may be reassembled.

One of the more successful examples of object/relational mapping in the world of open source code has been JBoss's Hibernate project. With JBoss now owned by Red Hat, the dominant enterprise Linux distributor, Sun turned elsewhere for its "reference implementation" of Java object/relational mapping.

Oracle leads an Eclipse project nicknamed EclipseLink, a play on Oracle's commercial product name, TopLink. A year ago, Oracle contributed TopLink code to the Eclipse Foundation and agreed to lead an Eclipse project that would use TopLink functionality as its core.

For Sun to select EclipseLink, it was necessary for three parties that haven't always worked well together to get together. Sun is not a member of Eclipse, whose open source programmer's workbench was based on a donation by rival tool vendor IBM. The Eclipse workbench became a unifying force among Java tool makers, allowing tools to swap files. Sun competes on Java tools, and as Java's originator and supervisor, once envisioned such a role for itself.

Oracle has always been a strong Java vendor, and competes with SAP on the strength of its growing portfolio of Java applications. Java's guardian, Sun, recently plunged into the database market by spending $1 bilion to acquire one of Oracle's more serious long-term threats, open source MySQL.

But the EclipseLink project will fulfill one of the key purposes of Sun's goal to build out the Java Enterprise Edition environment. It will give Java an efficient API for object/relational mapping. The Sun-led Java Community Process, which builds out Java, is assembling a set of interfaces known as the Java Persistence API, and EclipseLink will be a key component of that standard.

Sun had the option of choosing a similar project at the Apache Foundation, the OpenJPA, based on a donation of code from BEA Systems. BEA is now owned by Oracle.

"Using EclipseLink as the reference implementation ... is another great example of the Java Community Process and Eclipse communities working together," said Mike Milinkovich, executive director of the Eclipse Foundation in a statement announcing the choice at EclipseCon 2008 in Santa Clara, Calif., on Tuesday.

The EclipseLink object/relational mapping is slated to become part of Sun's open source Glassfish application server project. Glassfish, as it gains functionality, may start to compete more effectively with JBoss, the dominant open source application server.

Doug Clarke, Oracle's principal product manager for TopLink, said TopLink will continue as an Oracle commercial product, but future TopLink development will follow the path plotted by the EclipseLink project.

Other parts of the Java Persistence API will allow Java applications to have a simple interface for dealing with complex XML documents and data. Another will add an interface for IBM-sponsored Service Data Objects. But for the moment, getting basic object relational mapping right is a Sun and Java developer community priority, and they're relying on Eclipse and Oracle to get it done.