American Express | Full Stack Developer | Gurgaon | Mar 2023 [Offer]

Application Process

In March 2023, a recruiter reached out to me after finding my profile on Naukri.com. The entire interview process consisted of three online rounds and took about one month to complete.

Interview Round 1 (Technical: 1.5 hr)

This round had three interviewers: two with 1.5 years of experience and one with over 8 years of experience. I had previously informed them that I possessed basic knowledge of React JS, so the questions in that area were fundamental.

General & React JS Questions:

• I started by introducing myself.
• I then discussed my current project in detail.
• The React questions covered foundational topics:
• Do I use functional or class components?
• How do I transfer data between components?
• Explain stateless vs. stateful components with examples.
• Describe the React lifecycle in detail, including scenarios for each stage.
• Explain ComponentDidMount and ComponentWillUnmount with code.
• An output code question related to React was given on chat, and I was asked to share my screen to solve it.

Java Questions:

• What is a marker interface? Explain in detail with examples.
• Describe the thread lifecycle.
• What are the different methods to create a thread?
• Discuss ways to manage deadlock.
• Explain serialization/deserialization in detail.
• What Spring and Java versions am I using in my current company?
• What are the differences in features between Java 8 and earlier versions?
• Describe different types of memory and how Java utilizes them.
• What is immutability? Why is String immutable in Java?
• Explain the singleton class with code.
• Have I used Reflection API or Stream API?

Coding Problem:

I was given a problem involving two classes: class Student { id, section, house } and class School { id, name, Student id }. Given a List<Student> students and a List<School> schools, the task was to create a map where the key is the school name, and the value is a list of student IDs associated with that school.

Interview Round 2 (Technical: 1.5 hrs)

This round involved two senior engineers, one specializing in frontend and the other in backend.

General & React JS Questions:

• The round began with me introducing myself and discussing my current project again.
• The React questions moved towards design and concepts:
• If 10,000 requests are coming to my API, how would I handle it?
• Explain JWT authentication in detail, as I had mentioned working with it.
• Describe the types of memory in a browser.
• How would I handle a scenario where I've logged out of Facebook from one tab, but it needs to log out from all other open tabs in the browser using React?
• What is middleware, and have I worked with any?
• Another question on React lifecycle was asked.

Java Questions:

• What is the Stream API?
• Several questions on multithreading concepts.
• An output question related to call by value/call by reference.
• Discuss exception handling in detail: types of exceptions, common exceptions faced, and resolution strategies. An output question on exception handling was also included.
• Explain the difference between Throwable and throws.

Interview Round 3 (Tech + Managerial: 1 hr)

This final round was heavily based on my resume, discussions around my current project, and behavioral questions.

• I was asked to explain my project in depth.
• Which REST API methods have I used in my project?
• How do I optimize my code if I'm getting multiple requests simultaneously?
• Explain the application deployment process in my current company.
• How do I resolve merge conflicts in Git?
• Why am I leaving my current company?
• What products of American Express am I aware of?

Post Interviews

The recruiter reached out to me right after my final round to inform me that I had been selected. Within one week, they requested my details, and I received my offer letter two weeks after my selection.