There was a point a few years ago when many developers thought that the "language wars" were over: Java (or at least the JVM) was the new standard, and everything going forward would revove around that. Oh sure, things like Smalltalk would still exist around the periphery, but the thinking was that "everything" would end up on the JVM.
Things didn't quite end up that way, and Apple's dominance in the mobile space has a lot to do with that. While they are no longer forcing their favored languages on IOS developers, it's clear that most IOS work will be in Objective-C. That left Apple free to deprecate Java for the Mac, which makes a rather large dent in the Java "write once, run everywhere" story".
Not that Java is hurting - it's the preferred language for Android development, and Android is surging. There are a few issues, notably Oracle's lawsuit - but Java will remain one of the main development tools.
Another consensus changer over the last few years has been Ruby - it didn't all end up on the JVM. Meanwhile, Microsoft has had bigger problems with .NET than they thought they would. The upshot? It's still a diverse landscape for software developers.