Convert any object to pretty HTML in java

You could create an XSLT style for the XML output of xstream on your object.

You could relatively easily write your own library for doing so. Here's some example code that you could modify relatively easily to show html. Another option is to display the JSON inside a code tag in html. One final option is to use ReflectionToStringBuilder in apache commons lang and again show the result inside of a code tag in html. Using apache commons is probably no better than the json format however.