We (Oracle) have a lot of customers and partners who are interested in accessing low-level I/O like GPIO, I2C, UART and similar interfaces from Java ME and SE. We have for a while been working on a library that provides this sort of functionality. We are now open sourcing this in OpenJDK and are inviting community members to help enhance and extend this library, as well as port and optimize it to different types of hardware.
There is some overlap between our Device I/O and Pi4J. Pi4J is (and will remain) much richer in functionality, but was really intended for the Raspberry Pi and not for other platforms. We have been discussing with Robert Savage (Pi4J author and frequent contributor on this forum) how to handle this overlap and the current thoughts are that Device I/O may be the right place to handle the basic I/O with Pi4J as a rich layer on top. We have a similar thread going with some of the LeJOS (Java on Lego Mindstorms) community members.
With Oracle's investment in Java for embedded devices and Internet of Things, there will be more announcements like this one. Stay tuned!
For more information see:
Henrik, Oracle Java team