A really great way to earn some easy money on bug bounty programs: pay attention to popular vendor's bugs.
Vulnerability
https://issues.apache.org/jira/browse/SOLR-4861
Here are a few Solr services which run on Jetty. http://www.shodanhq.com/search?q=solr+jetty
Add in some correlation magic and one will find a few vulnerable services which have bug bounty programs.