Lots of reasons: 1) Everyone knows it or has touched it. Walk down a street filled with developers and you'll run into many who know or have worked with Java.

Lots of reasons: 1) Everyone knows it or has touched it. Walk down a street filled with developers and you'll run into many who know or have worked with Java. 2) Apache. Apache. Apache. The saying goes No one ever got fired for using Java / no one ever got fired for using apache. Most major apache projects and libraries are Java/JVM based and the Java interface provides the best way to interact with them. Don't underestimate the pull from Apache on language choice. 3) Libraries - people have spent millions of man hours developing libraries for Java/JVM languages that aren't replicated elsewhere. Odds are pretty good if you're looking for an open source library that does X someone wrote it for the JVM. 4) Legacy Systems. Java is the new COBOL. There are billions of lines of Java code in existence chugging away around the world. It's more expensive to overhaul and replace an entire code base than it is to find or train developers to work on it. 5) People are riffing on top of the JVM. Rather than fight it, all the new hot languages like Clojure, Scala, Groovy, etc. are building on top of the JVM and taking advantage of what it gives you under the hood and the fact that the JVM has a wide install base. This reduces the likelihood Java will die in many capacities since it's being pushed into a more key infrastructure role rather than outright replaced. Edit: fixed spelling