How does Java 8 Stream: sort by an attribute under a sub-object in an object?

I have an object List, such as List < Main >, a property in Main is a Sub object, and an attribute id in Sub.
I want to sort by Main.Sub.id. What should I do?

list < Main > .stream (). Sorted (Comparator.comparing (Main::getSub)) cannot be sorted by id.

Stream java8
Mar.02,2021

list.stream (). Sorted ((Sub1, Sub2)-> Sub1.getId (). CompareTo (Sub2.getId (). Collect (Collectors.toList ());

are you sure that answer is valid?

Previous: On the return value of vue filter

Next: How to subtract two dataframe?

css mysql arrays josn react html typescript webpack npm sass R objective-c .net sql-server jquery python-3.x angularjs django angular excel regex iphone ajax linux xml pandas vba spring database wordpress string wpf xcode windows bash postgresql oracle multithreading eclipse list firebase algorithm macos forms image scala visual-studio azure bootstrap spring-boot react-native python-2.7 docker performance function winforms matlab powershell apache dataframe api sqlite numpy rest shell selenium flutter dart maven loops qt swing android-studio csv express file class tensorflow sorting codeigniter perl
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b38093-2c0c7.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b38093-2c0c7.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
Need Help?