Why not use java for your java application

I'm using java over five years, but most of my webs are running on php scripts due to the high quality of WordPress and vBulletin. On the other hand, roller is the most stable blog system running on java, but it lacks of templates and mods. Meantime, due to only focusing on an enterprise application, it is very hard to install and configure.Jive is a java forum systme of high quality, but it's too expensive, most of webmasters can't afford $5k to buy a forum system, anyway, you can get a copy of vBulletin only by $180. Another reason is that there have more php web hosting than java, btw, you can find few free java hosting from java resources.
In one word, Java application is only for enterprise application.