I directly received a call from HR, who arranged a series of 4 interviews (no written test). Every interview started with a casual introduction; the rest of the details are below.

Interview 1

• Started with a coding problem: "Find quotient and remainder when given two numbers." After that, I was asked to write test cases for all possible use cases. My code failed when dividing with negative numbers, so I fixed all issues on the go as we were testing it.
• Puzzle: 10 coins, 10 lines puzzle.
• Explain divide and conquer sort and write code for one such algorithm (I wrote Heap Sort).
• A few Java and REST API questions.
• One more puzzle question that I cannot recall.

Interview 2

• Started with a coding question (based on a greedy algorithm), again with test cases for that algorithm.
• Puzzle based on syllogism.
• Questions on REST API.
• A few Java questions.
• One more puzzle which I can't remember.

Interview 3

• Introduction.
• Test approach for a hypothetical use case and how I would automate it.
• Puzzle question (Birthday puzzle).
• Coding question (Array rotation).

Interview 4

• Introduction.
• Basic core Java questions.
• Questions based on my favorite subject (Operating Systems).
• Puzzle (Least number of weigh-ins required to find impurity).

Write any one divide and conquer sorting algorithm.

What is dynamic binding in Java?

Explain garbage collection in Java.