It was 4 rounds in the morning, lunch, and then 3 rounds in the evening. Each round had a general question on my thoughts on certain things like Javadoc, the Agile process, and design considerations, followed by a technical question. The interviewers were knowledgeable and shared their thoughts; they were also very technically sound.

The best way to prepare, I would say, is to go through Amazon interview questions on LeetCode.

1. Verify if two nodes in a graph have the same parent or not.
2. LCA of a BST and Binary Tree.
3. Explain how merge sort works.
4. Buy Sell Stock: Single Transaction.
5. In an array, find all unique elements that add up to a sum.
6. How garbage collection works. If A points to B and B points to A, will they be collected? [Yes]
7. Query: Find the second highest salary employee.
8. Implement LRU in Java.
9. If the input is a paragraph with punctuation, find the total number of distinct words, the total number of words, and the word with the highest count.
10. Schema-related questions to create a product/ordering system, and how to handle price changes and multiple counts of the same product in a cart. And a few more I forgot.