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Sun Persists with Single Programming Model

UPDATED: Engineers at Sun Microsystems have agreed to sift through Enterprise JavaBeans (EJB) and Java Data Objects (JDO) to create a single persistence model, called Plain Old Java Object (POJO), for developers.

Sun said in a statement the idea is to unify the Java community, which has been fractured by the coexistence of EJB , the component architecture for the J2EE platform and JDO, which lets programmers directly store Java domain model instances into a database.

In an open letter, officials for the Santa Clara, Calif., company said EJB, also known as JSR-220, and JDO, or JSR-243, have proven to have very different data persistence models over the years, causing confusion among users.

Linda DeMichiel and Craig Russell, stewards of JSR-220 and JSR-243, respectively, said the company is expanding the JSR-220 Expert Group to include some members from the JSR-243 Expert Group in an effort to "bridge the two communities and leverage the know-how in both groups."

In asking for the Java community's support, DeMichiel and Russell said: "We believe this is a unique opportunity for the Java community to create a common POJO persistence model for both J2SE and J2EE ... By incorporating best-of-breed design concepts, this common POJO persistence model will further strengthen the Java platform."

The news drew cheers from officials at Versant, which makes data persistence software.

"This is great news for the Java community," said Keiron McCammon, chief technology officer of Versant. "Java developers now have a clear roadmap of how the JDO and EJB specifications will come together. The new persistence API will draw together the best aspects of the JDO 2.0 and EJB 3.0 specifications as they exist today."

Sun hopes to provide a single object/relational mapping facility for all Java application developers that works in both J2SE and J2EE.

EJB is moving toward its third iteration, while JDO is heading toward its second. The current JSR-220 specification lead will remain unchanged, and the work to define a single POJO persistence model for the Java community will be done under JSR-220.

The new POJO persistence model will be delivered by JSR-220 independently of EJB 3.0. The work will be done within the J2EE 5.0 time frame, DeMichiel and Russell said in the letter.