As the article points out, Java itself isn't most popular in the niches it was supposed to fill. I don't think it's really appropriate to talk of what they were

As the article points out, Java itself isn't most popular in the niches it was supposed to fill. I don't think it's really appropriate to talk of what they were grown to solve. What they are actually used for is far more illuminating, and while Ruby is encroaching more and more on Java's "home turf," especially now that JRuby has the momentum and capability it has, you can't really say the same the other way.