> Will start with the docs as you suggested. To add to that, I recently created a "top ten" list of files that seem important and have no top level Javadoc. These might be a useful place to start.
solr/core/src/java/org/apache/solr/core/CoreContainer.java solr/core/src/java/org/apache/solr/handler/admin/CollectionsHandler.java solr/core/src/java/org/apache/solr/update/processor/DistributedUpdateProcessor.java solr/core/src/java/org/apache/solr/handler/StreamHandler.java solr/core/src/java/org/apache/solr/cloud/ElectionContext.java solr/core/src/java/org/apache/solr/handler/component/RealTimeGetComponent.java solr/core/src/java/org/apache/solr/update/DefaultSolrCoreState.java solr/core/src/java/org/apache/solr/search/JoinQParserPlugin.java solr/core/src/java/org/apache/solr/handler/component/HttpShardHandlerFactory.java solr/core/src/java/org/apache/solr/handler/SolrConfigHandler.java I've been meaning to add an ant target so checkstyle can detect these automatically, but I haven't gotten around to figuring out how to add a dependency to the build. - Bram
