SavaJe Technologies is the developer of the SavaJe XE operating system, an OS designed to run only Java applications, and, according to SavaJe, "to run them very well." SavaJe XE is available for the Compaq iPAQ device as well as the Psion NetBook, but there's a catch. Installing SavaJe, like the installation of any operating system, requires that the existing operating system on these devices be removed. One drawback that has kept me from actually installing the OS is the fact that SavaJe provides no support for the reinstallation of, for instance, Windows CE on the iPAQ. So be sure that you're prepared to live with SavaJe before proceeding. If you're sure, you can take advantage of SavaJe's greatly improved Java performance, small overhead, and complete J2SE support.