Sun says its JXTA technology for peer-to-peer computing is gathering steam and may soon make its way into some of its own products.The number of developers who have downloaded the free JXTA code from the Web passed 2 million recently, up from about a million last March, said Juan Carlos Soto, director for advanced technologies at Sun. The number of developers who have registered at http:\/\/www.jxta.org is much lower, however, at about 16,200, up from 12,000 a year ago."There's a lot of interest in JXTA out there and a lot of developers are working with the technology," Soto said.A key goal at Sun has been to make JXTA better suited for use in commercial applications. In December it released Version 2.2 of the Java 2, Standard Edition implementation of JXTA, an upgrade which focused on improving security and performance. A further release, with the code name Churrasco, is due in March.Unveiled almost three years ago by Sun's then chief scientist, Bill Joy, Jxta provides a communications mechanism for linking peers - such as a PC, server, phone or PDA - in a distributed network. Such peer-to-peer networks typically aren't run by a central server, and JXTA provides a way for the peers to locate and communicate with each other directly.It is offered under an open source license, which means developers can tinker with the code. It is also free, making it attractive to some. But the fact that it is free has also been a source of criticism. Some analysts have wondered what Sun gets in return for its investment in developing Jxta, and why it hasn't made use of the technology itself.That may be about to change. JXTA is mature enough that Sun will soon be using it in some of its own desktop and server products, Soto said. "What you are going to see is more and more Sun products start to include the JXTA technology in them," he said.Sun has already shown how JXTA could work as part of its N1 system for managing data centers. Installed on a group of servers, the technology can be used to indicate when servers go on and offline, and help to allocate computing jobs accordingly, Soto said.JXTA may also find its way into Sun's Java Enterprise System, a bundle of server software formerly called Sun ONE. For example, it could be used to improve the performance and scalability of the IM component, in part because JXTA is unhindered by firewalls and network address translators, Soto said."Some of these things will be coming out pretty soon," he said, declining to be more specific.In an effort to show that interest in JXTA is growing, Sun is also highlighting companies using JXTA in their applications. One of them is Verizon Communications, which is using JXTA as part of an upcoming service called iobi, an advanced call management service designed to help customers juggle calls between their work, home and cellular phones.As part of the service, due later this year, iobi will be able to set up a data channel automatically between two PCs, so that callers can exchange files or collaborate on documents. Iobi uses Jxta to locate those PCs on a network and establish the connection, said Nosh Minwalla, a Verizon senior architect.Linking the PCs in a peer-to-peer fashion is preferable because it saves the expense of running an e-mail server and storing files there, he said. JXTA also helps "tag" the data files so they are tied to a particular voice call. At the end of the day a user can view all related calls and file transfers in one list, Minwalla said.Verizon explored other technologies, including Gnutella and some peer-to-peer tools that Microsoft recently introduced. It picked JXTA mainly because "it's very extensible - there aren't a lot of restrictions on how we run our applications," Minwalla said. It also liked that the software is open source, and that it can handle firewalls and NATs straight out of the box, he said.Another company using the software is Nokia, Soto said. The company installed JXTA on some of its infrastructure servers used internally, creating a peer-to-peer server network. "When one of these servers comes online or goes offline it is automatically discovered, and when it does come back online you can send the latest software to it," Soto said.Yet another company, Brevient Technologies of Milwaukee, used JXTA as a communications protocol for its file sharing and Web conferencing product.To give users more visibility into what's coming, Sun has also published a roadmap for JXTA. It has also switched to releasing updates on a quarterly release cycle, as it does with its other products."Our main focus is around the areas that we think will enhance the capabilities for enterprise use - that's around enhanced security, enhanced performance and simplifying the APIs (application programming interfaces)," Soto said.