I don't think WORA was ever a really big deal for server-side work. In practice, you know what platform you're developing for, and even if you were developing on Windows and deploying on Solaris, you would have plenty of opportunities to test on Solaris before deploying.

I think the reason that Java beat C++ for boring line of business apps is that it was much, much quicker to write code which ran fast enough and didn't crash much. Having nice easy to use URL/HttpURLConnection classes built in was probably also a surprisingly big part of it!