docs: private SolrServer initCore(String coreName) {
  		try {
  			String uri = config.getString(null, "indexer", coreName, "uri");
  			if (uri == null) {
  				log.error("No URI provided for core: '{}'", coreName);
  				return null;
  			}
  			URI solrUri = new URI(uri);
  			CommonsHttpSolrServer thisCore = new CommonsHttpSolrServer(solrUri.toURL());
  			String username = config.getString(null, "indexer", coreName, "username");
  			String password = config.getString(null, "indexer", coreName, "password");
  			usernameMap.put(coreName, username);
  			passwordMap.put(coreName, password);
  			if (username != null && password != null) {
  				UsernamePasswordCredentials credentials = new UsernamePasswordCredentials(username, password);
  				HttpClient hc = (thisCore).getHttpClient();
  				hc.getParams().setAuthenticationPreemptive(true);
  				hc.getState().setCredentials(AuthScope.ANY, credentials);
  			}
  			return thisCore;
  		} catch (MalformedURLException mue) {
  			log.error(coreName + " : Malformed URL", mue);
  		} catch (URISyntaxException urise) {
  			log.error(coreName + " : Invalid URI", urise);
  		}
  		return null;
  	}