American Express Interview Experience for Full Stack Developer (1.5 YOE)

Total rounds – 3Verdict: SelectedRound 1–

3 interviewers were there2 interviewers with 1.5 YEO, 1 with 8+ YEO

I had informed beforehand that I have basic knowledge of React JS. So question level was also basic. Tell me about yourself. What is the current project you are working on?

Sure, here are the questions you provided:

React:
1. Do you use functional or class components?
2. How do you transfer data between components in React?
3. What are stateless and stateful components, with examples?
4. Can you explain the React component lifecycle in detail? Provide scenarios where each phase is used.
5. Explain the concepts of `componentDidMount` and `componentWillUnmount` with code examples.

Java:
1. What is a marker interface? Could you provide examples?
2. Explain the lifecycle of a thread.
3. What methods can be used to create a thread in Java?
4. How can deadlocks be managed or avoided? 
5. What is serialization and deserialization in Java?
6. What versions of Spring and Java does your company use?
7. Highlight the differences in features between Java 8 and Java 11.
8. Can you describe different types of memory and how Java utilizes them?
9. What is immutability? Why is a string immutable in Java?
10. Provide an explanation of a singleton class along with code examples.
11. Have you utilized Java reflection or Stream API?

Data Structures:
1. Define a class `Student` with properties: id, section, house.
2. Define a class `School` with properties: id, name, Student idList.
3. How would you create a map with keys as school names and values as lists of student IDs?

Round 2–

Tell me about yourself. What is the current project you are working on?

Certainly, here are the questions you provided:

React JS:
1. If 10k requests are coming to your API, how will you handle it efficiently?
2. Explain JWT authentication in detail, considering your current project’s context.
3. Can you list the types of memory in a browser?
4. Given the scenario where you’ve logged out of one tab on Facebook, how would you ensure that you’re logged out from all other tabs using React?
5. What is middleware in the context of React? Have you worked with any middleware before?
6. Discuss the React component lifecycle.

Java:
1. What is the Java Stream API?
2. Could you explain the concept of multithreading in Java?
3. Explain the differences between call by value and call by reference, and provide an example of an output question.
4. Describe exception handling in Java. What are the different types of exceptions? Can you share common exceptions you’ve encountered and how you resolved them? Provide an output question related to exception handling.
5. Compare `Throwable` and `throws` in Java.

Round 3–

Tell me about yourself

1. Can you explain your project in detail?
2. What REST API methods have you utilized in your project?
3. How would you optimize your code to handle multiple simultaneous requests effectively?
4. Describe the process of deploying applications in your current company.
5. What approach do you take to resolve merge conflicts in Git?
6. What is the reason for your decision to leave your current company?
7. Could you list the AmEx products you are familiar with?

This round was mostly based on my resume, discussion around my current project, and some behavioral questions were asked

I hope this experience can help you!

All the best for your interviews.