Message Title

The current code is misleading and in some respect plain wrong. Here is the existing code:

try {
	String databaseName = config.getDatabaseName();
	log.connectingToMongoDatabase( databaseName );
	Boolean containsDatabase;
	try {
		containsDatabase = mongo.getDatabaseNames().contains( databaseName );
	}
	catch (MongoException me) {
		// we don't have enough privileges, ignore the database creation
		containsDatabase = null;
	}
	if ( containsDatabase != null && containsDatabase == Boolean.FALSE ) {
		if ( config.isCreateDatabase() ) {
			log.creatingDatabase( databaseName );
		}
		else {
			throw log.databaseDoesNotExistException( config.getDatabaseName() );
		}
	}
	DB db = mongo.getDB( databaseName );
	if ( containsDatabase == null ) {
		// force a connection to make sure we do have read access
		// otherwise the connection failure happens during the first flush
		int retries = 0;
		while (true) {
			try {
				db.collectionExists( "WeDoNotCareWhatItIsWeNeedToConnect" );
				break;
			}
			catch (MongoTimeoutException me) {
				// unless we retry twice, the second access will be aTimeoutExceptionerror instead of an auth error
				// This is a workaround for https://jira.mongodb.org/browse/JAVA-1803
				retries++;
				if ( retries > 2 ) {
					throw me;
				}
			}
		}
	}
	return mongo.getDB( databaseName );
}
catch (MongoException me) {
	switch ( me.getCode() ) {
		case AUTHENTICATION_FAILED_CODE:
			throw log.authenticationFailed( config.getUsername() );
		default:
			throw log.unableToConnectToDatastore( config.getHosts().toString(), me );
	}
}

The idea is to check whether the specified database exists (using getDatabaseNames) and then depending on config.isCreateDatabase() create it (implicitly, since just calling getDB will create it). This makes really only sense if the database runs in no-auth mode. If the database runs with authentication, the user and database need to exist in the first place, otherwise an authentication error occurs. There is really no point to call getDatabaseNames anymore.
Also the current code does just check the authorization error code (18) and in all other cases assumes that there is a privilege problem. That is not the case and should be explicitly tests (see https://github.com/mongodb/mongo/blob/master/src/mongo/base/error_codes.err). The error code of interest is "Unauthorized", 13.
Last but not least, collectionExists to indirectly check whether the user has read access (which btw I think is a given and if anything we should check for readWrite access). This should be really replaced with something like:

BasicDBObject commandArguments = new BasicDBObject();
commandArguments.put("user", <user>);
commandArguments.put( "db", "<dbname> );
BasicDBObject command = new BasicDBObject("usersInfo", commandArguments);
CommandResult result = db.command( command );

The result contains the permissions of the given user for the specified database.