The question for today is, should you care?
An open source Java project, OSJava, has existed for over a year. The Apache Harmony project, which has been around since last May. Helmi Technologies launched an open source AJAX project, which includes Java, just this month. There's an open source clean room version of the Java Virtual Machine called Kaffe, there's an open source Java webring, and even Sun admits open source Java won't change your life.
The real deal here, as Tim O'Reilly noted 16 months ago, is that Java is losing market share and mind share. The passion to open source Java has cooled considerably since Eric Raymond wrote his 2004 letter begging for Java to be let go. Things like Glassfish are, in fact, swimming upstream.
Just as with many other open source projects, the Java move is defensive. It's meant to make Java more competitive with Microsoft's .Net.
Will it? You decide that.