According to a Forester report the multiple IDEs for Java developers is standard practice:
While Eclipse is common, it won’t become the only Java IDE in enterprise IT shops any time soon. Less than one out of five Java developers have a single primary Java IDE and no other.
— Jeffery S. Hammond (Forrester Research)
As a victim of attempts to standardize on a single IDE, this is a good counter-weight argument. My personal experience is I primarily work on Java code in IntelliJ IDEA, but every once in a while I want to use some specific Eclipse plug-in. More regularly I’ll drop back to TextMate for some Groovy or Ruby work as well.
Despite the efforts of commercial vendors to sell IT management on the concept of higher productivity with their brand of IDE, the idea hasn’t worked. At the end of the day as a developer in any shop I want to know I can pull down a codebase and run an automated build with no IDE at all. I don’t care if the original developer did it in Eclipse or Netbeans. The key to being a successful coding shop is to remember that IDEs are just tools and should never be required to build, test, or deploy an application.