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Tag: stream

How to match equals() and hashCode in streams?

I have a stream where I am aggregating some data like this: The problem is that by adding this comparator I am braking the contract between hashCode() and equals() and at the end I have duplicate keys: Has anyone some ideas how can I fix this? Or is there a way to sort the final object ( Map<String, Map<String, Map<EventType,

Set with Optional

I have this code: I want to replace this code to this: and map this field from myClass to myClass2 How i can do it? Answer Did you mean to use: For mapping I would suggest to read about MapStruct, it is a good tool.

Sort A List of an Object with other object’s method

In the bellow code, with such classes, how can I sort an ArrayList of Students by the score the got from Courses List? I mean how can I sort a List of a specific class by an attribute of this class which is a child of another class. Answer Your “Student” class is confusing. Based on the name, it sounds