Solr - Debug Solr with Eclipse

This post has great description of how to debug Solr with eclipse.
NOTES:
1. If you want to step through Solr's source code. You may want to comment out cache configurations in solrconfig.xml (solr/collection1/conf/solrconfig.xml). Otherwise, it would step through the code using cache after you first run a query.

2. The entry point for a Solr "select" request is SolrDispatchFilter.doFilter. (org.apache.solr.servlet)