There are several Solr APIs that are handled as first class citizens in SolrJ, esp. the Node API and the Collections API, i.e. they have their own xxxAdminRequest Object extended from the SolrRequest Class. As someone who programmatically changes Schemas a lot, I had hoped to see the Schema API handled first class in release 5.0, too. As far as I dug into the code and docs of SolrJ 5.0, that did not happen. If there is a reasonable point why this won't happen at all, I would really like to hear it. If the only reason is, that nobody had time for this, I would happily help out here.