There has been some recent news about IBM joining the OpenJDK project. The OpenJDK project is an open source project aimed at creating an open source implementation of the Java Development Kit. Formerly, IBM worked on a competing project sponsored by the Apache Software Foundation (ASF) called Apache Harmony. OpenJDK is supported by Oracle, which is currently suing Google over Java technology that they claim is improperly used in the Android platform. IBM's defection is important for a number of reasons.
Not Fully Open Source
It is important to understand that Java was initially a proprietary technology. Sun Microsystems developed and owned the Java platform. As Java's acceptance grew, so did calls for Sun to open source Java. While Sun did not go quite that far, they did establish the Java Community Process as a method for the community to provide input into Java's direction and future.
Over the course of time, Sun began to bless open source versions of Java. There were still many licensing restrictions however. Apache Harmony was created as an open implementation of Java. The Harmony project sought a less restrictive license from Sun. However, they did not receive it before Sun was purchased by Oracle. Incidentally, this is the basis for the Oracle lawsuit against Android. Android uses class libraries from Harmony and Oracle believes that the Harmony project's license for Java technology does not allow for it to be used in the way that it is used in Android.
The OpenJDK was another project that aimed at an open source implementation of Java. Oracle supports the OpenJDK project. Now that Oracle owns the Java technology this seems to carry more weight. IBM was promised a lead role on the OpenJDK project which lead to them moving their resources away from Harmony to the OpenJDK.
With that summary of the backstory, why does it matter? One obvious reason is that Oracle's lawsuit against Android has caused many to doubt Java as a suitable platform. IBM has a strong reputation in the open source community. By getting IBM to endorse and contribute to OpenJDK, Oracle can hope to improve its image in the open source community. The open source community is important to Java's continued success and Oracle has a very poor image in this community.
Apache Harmony: Future Uncertain
By reallocating its resources to the OpenJDK, IBM has likely signed the death certificate for Apache's Harmony project. IBM developers accounted for about one third of the Harmony project's resources. Unless Google decides to pick up Harmony, which is possible since Google does use Harmony in Android, Harmony is unlikely to have the resources to continue.
Finally, what is IBM getting from helping Oracle polish their image? IBM has built a considerable amount of technology using Java. If Java's future were to become uncertain among technology leaders, they may select non-Java technology. By helping Oracle reassure the technology world about the soundness of using Java and the availability of an open source, freely licensed implementation of Java, IBM is reassuring its own customers.
This move to support OpenJDK by both IBM and Oracle is motivated by practical business concerns by both companies. The potential loser is the Apache Harmony project unless Google becomes involved. It will be interesting to see if that happens and how this move affects the future of Java and its perception among technology leaders.