There are a plethora of reasons that the enterprise uses Java and many of them are really good reasons but the main reason now is inertia, so many enterprises and vendors are invested in Java that to divest of Java just does not have a good value proposition, given the fact that their has not been a major revolution in languages or run-times, no one has had the stomach to try to move off in a serious attempt.

To understand it we have to look at the history of when Java came about and what Java brought to the table. Most people think it was a more modern language that was what won but the reality is that was just icing. The real winner for Java taking over was the VM, at the time Unix was dominating the server space (in particular Solaris) but Microsoft has a through monopoly on the desktop. So here you had all of development on one OS and all of the runtimes on another, The promise of Java was that your developers could continue to develop on desktops while delivering to Server architecture, it was not always totally smooth but it did work and their in lies the revolution that Java brought. A common development platform across architectures. It seems so common today but at the time it was huge, it had the potential to save companies millions if not billions.

Fast forward to today and a big issue with the enterprise is labor, and lets face it trying to take the road less traveled can introduce unnecessary risk into the enterprise. If a company is not in the Vally the quest to find a Ruby or Python or Node.js developer can result in not finding a single candidate, this is far more risky than another month of development time to stay with Java. They are totally different concerns, a small scrappy start up, can afford to kick the bushes of local groups to find a guy playing around with Node.js, an enterprise has no systematic way of figuring out if the kid at the local users group is an expert at Node.js or has just been playing with it for 2 weeks. To me this is the biggest one, talent is available locally and even if it is not, the big vendors and even the recruiters can dig someone up fast. This alone mitigates a lot of risk from the organization.

Second most enterprise software is built with Java and has Java API's, SAP, Oracle, IBM and many of the other offerings these guys use are in Java. I like to poke a lot of fun at some of those systems but the reality is implemented correctly they can save a lot of money and time and unlike in a start-up where every penny counts in the enterprise vendor supported systems are considered a good thing. They allow the company to focus on their core business while leaving system development to a vendor.

Which brings me to my last point, there is a new revolution underway, and I do believe that in the near future the cost benefit analysis is going to be so great that the enterprise will not be able to ignore it, and that revolution is SaaS. For the same reason I just highlighted, (focusing on core competency), SaaS will be huge, now not only will the enterprise not have to concern itself with maintenance of custom systems, but they will be able to offload support as well as infrastructure. Getting out of the infrastructure game for the enterprise will be huge and may herald the end or Java's dominance.