MasterCard Pune || SSE || Level 7

Interviewer asked me about the my current responsibilities and then started asking about tech-stack. Then we asked me to explain my current project request flow. After wasting 30 minutes on it. He...

Interviewer asked me about the my current responsibilities and then started asking about tech-stack.
Then we asked me to explain my current project request flow.

After wasting 30 minutes on it. He asked me two questions and closed the interview.
Overall experience was bad and HR made it worst by not sharing the interviewer\'s feedback.

Question:
1. Using stream, create a map of <String,List> where Employee is having age and name as attribute, where empployee is having ("Ankit",32) ("Mayank",40)("Rahul",32)("Niky","24"). Then I want to group the employees by their age e.g. 20-30, 30-40, 40-50, 50-60, final map should be "10-20",{} "20-30",("Niky","24"), "30-40",("Ankit",32) ("Mayank",40)("Rahul",32)
He told me to make it generic. Even chatgpt was not able to do it single stream code when I checked it later.
2. Using Java(without any framework),
From main processing function, I want to call API 1 async and then call API 2 async, call API 3 sync and then wait for response for API 1 and 2 response.
Someone like me who already mentioned that I know the thread concept but he still not convinced with my ans. Also I made me to code on editor( no auto suggestion)

Interviewer was not at all supportive, he just asked me 2 questions and did not even attempt to give any hints or suggestion wherever I was stuck.
Bad experience.