Java openness is particularly attractive because it makes the code written in Java portable to other operating systems. From time to time, clients may decide to change their operating system, or may want to produce the same system on an additional operating system, without having to change the code written on the original operating system. For this reason, Apachean Open Source Web server created by the Apache Software Foundationhas been ported to all the main operating systems to encourage its proliferation. This technique has worked, with Netcraft showing that Apache is the most widely used Web server by a vast margin.
Thus, when a client decides to use a new operating system, none of the Java code has to change, and the Web server can stay the same. This makes changing systems so much easier.
Where clients have put portability and interoperability at the top of their requirements lists, I suggest Apache, Java, JDBC, and XML on top of one of the 'nixeseither Linux or one of the UNIXes (Solaris, AIX, HPUX, and so on).