This interview was mainly for Java Engineer. I appeared in 3 rounds of it.

Description of which is given below.

Overall, it was a good interview. Make sure you do your homework. Read about the company and its culture.

1st round: One to one with HR regarding qualification, experience, and skill set. And what Adyen is all about.

2nd round: Codility coding round. It was a 3-hour online coding test. They restricted the language to Java because my application was for a Java engineer. Here, there were 4 questions:

1. Problem-Solving Question: It was an array question.
2. SQL Query: This query involved joins and nested queries.
3. Bug Fixing: A problem statement was given. A method for the same was also given. This method contained a few errors, and our task was to find those errors and fix them. They restricted the code changes to only 2 lines, meaning I was not allowed to change more than 2 lines for this program. This was very tricky but was a medium-level code.
4. Program using Java Streams: A problem statement was given with all the classes and interfaces associated with it. I was asked to add a particular feature to that program using Java streams.

3rd round – Codility Review Code – Discuss all 4 questions – what was your approach:

• What is an integration test?
• Which version of unit tests do you use?
• How can you provide security while saving passwords in a database?
• How can you check the performance of a query?
• Discuss one of the tools upon which I worked.

Remarks: In the 1st and 2nd Codility questions, they said, "Mind-blowing approach."

For the 3rd question – bug fixing – they asked for my approach and then showed me that there was one test case I missed. My code changes were taking care of all the test cases except one. They showed me the correct answer and then said, "I agree that this was a tough one to guess."

For the 4th Codility question – they said, "Seeing the code, it seems like you got very little time for this." I said yes. They then asked me to explain the approach. I explained a few things, but not very properly, as I was unable to recall it fully.

1st round: One-to-one with HR regarding qualification, experience, and skill set. Also, learned what Adyen is all about.

2nd round: Codility coding round. It was a 3-hour online coding test.

3rd round: Codility review code – Discussed all 4 questions. What was your approach? And also, a few questions like:

• What is an integration test?
• Which version of unit tests do you use?
• How can you provide security while saving passwords in a database?
• How can you check the performance of a query?
• Discussed one of the tools upon which I worked.