driver-legacy/src/main/com/mongodb/DB.java
public CommandResult command(final String command, final ReadPreference readPreference) {
        return command(new BasicDBObject(command, true), readPreference);
    }
public CommandResult command(final String command, final ReadPreference readPreference) {
        return command(new BasicDBObject(command, true), readPreference);
    }
public CommandResult command ( final String command , final ReadPreference readPreference ) { return command ( new BasicDBObject ( command , true ) , readPreference ) ; }
Executes a database command. This method constructs a simple {@link DBObject} and calls {@link DB#command(DBObject, ReadPreference)
}.

@param command        The name of the command to be executed
@param readPreference Where to execute the command - this will only be applied for a subset of commands
@return The result of the command execution
@throws MongoException if the command failed
@mongodb.driver.manual tutorial/use-database-commands Commands
@since 2.12
Executes a database command . This method constructs a simple { @link DBObject } and calls { @link DB#command ( DBObject ReadPreference ) } .