Most profitable industry for JAVA/J2EE developers

The central question here is what is the hottest industry to be in as a Java/J2EE developer or Software Engineer in general. There are some industries that are more stable than others, however salaries and rates for software engineers in those industries are low too and have small growth potential. At the same time there are industries like Investment Banking where profit to total number of employees ratio is very favorable and people get great bonuses on full-time bases and high rates on contract bases.