Complete Interview Process | Java Developer

In this article, we are going to discuss the interview process for a Senior Software Engineer - Java role at Deutsche Telekom. There can be either 4 or 5 rounds depending on the role and the recruiter. The one extra round can be the initial online coding round.

Rounds-

Technical Round-1
Technical Round-2
Managerial Round

Technical Round-1

Given a tree, print the left view of a tree.
Can you tell HashSet Internal Functionality and write down code for a Custom HashSet?
Differentiate between HashMap and ArrayList
Which design patterns have you used? The interviewer can then ask for one design pattern, for example- Adapter Pattern
What is Dependency Injection? How does this work internally?
How does Spring MVC work? Can you tell the internal functionality?
What is Interceptor?

Technical Round-2

What are your most comfortable/used collections? The interviewer can then ask for any one collection?
Differentiate between HashSet and ArrayList
How does HashSet maintain the uniqueness of elements?
Questions on the time complexity of collection operations
What is a Singleton class & how to create it?
Can you create a synchronized Singleton class? How will you allow 5 threads into a critical section?
What do you understand by Executor Service?
How does volatile keyword work internally? Can we use volatile for a counter variable?
What are Dependency Injection types? Which injection type to use and why?
Do you know about Design patterns used by Spring internally?
What do you understand by Template & proxy design patterns?
How does @Transaction work internally?
What is Advice & types of advice in Spring AOP?