IntelliJ IDEA is very good for Java, and good also for other JVM languages. But how good it is depends, both on the effort put in by the IDE developers and characteristics of the programming language in question (how well operations in the IDE are supported by the typing characteristics of the language etc)

When in Java, there is a mishmash of supporting file types, and it integrates them very well compared to its competitors - jump between .java, .jsp, various .xml for Spring, Hibernate, tag libs, etc etc. If you are "just" programming in a programming language (which is a lost utopia in for J*EE developers), much of this functionality is not of much benefit to you, but you might still find the IDE valuable.