Open source Java - Hallelujah!
In Harmony's FAQ, Geir Magnusson (in charge of Geronimo ) explains that they could only start this project now because Sun changed the licensing rules in the JCP to better accommodate open-source software.
Sun, traditionally a very strong ally of ASF, seems a bit confused after this announcement. It's VP and fellow Graham Hamilton expressed some doubts about the need for Harmony in his blog : "Personally, I am not entirely sure if the world really needs a second J2SE implementation…" He adds: "Personally, I am very curious about how the Harmony project will work out - creating a full scale implementation of J2SE is a mammoth task, as the Sun J2SE team knows only too well.” In other words he is wishing good luck to the Harmony group, their task will be overwhelming and he is probably right. Anne Thomas Manes, from the Burton Group seems to agree with him as well, she thinks it will take a long time to build a clean-room J2SE implementation, "because it's a very big piece of code."
Another challenge facing the Harmony folks is to make sure they are extremely careful about IP issues. Apache's Geir Magnusson concludes his FAQ with: "Historically, there has been wide exposure to VM and class-library-specific source code that is the property of Sun Microsystems as well as others... We wish to make every effort to ensure that the licenses and rights of external projects and efforts are properly respected. To that end, we will explore additional ways to work with the Apache Incubator to ensure that all IP is carefully monitored and tracked as it enters the project."
If you would like to know more about Harmony, Geir will be speaking at JavaOne 2005.
A basic architectural diagram of Harmony is available at: http://people.apache.org/~geirm/harmony.jpg