You must be stuck up with Apex, when sorting is required on instances of user defined classes and pre-loaded Sobjects. Unfortunately standard Apex API just gives a method List.sort(), that just works with primitive data types.

So to get the job done, developers can implement their own sorting either using standard and simple bubble sort or some other complex sorting algorithm.

Read More: https://abhinav.fyi/sorting-apex-classes-sobject-using-apex-lang-code-share-project/