Caizin | Senior Software Engineer| January 2024 [Offer]
Summary
I received an offer for a Senior Software Engineer position at Caizin in January 2024 after successfully navigating through their interview process.
Full Experience
My interview journey for the Senior Software Engineer role at Caizin in January 2024 involved two main rounds. The process was comprehensive, covering both data structures and algorithms, alongside core Java and Spring concepts.
Round 1:
- I was asked to find the Longest Increasing Subsequence.
- A puzzle involving finding the minimum number of ways to guess a 4-digit lock value starting from '0000' was presented.
- We discussed the differences between Spring annotations like
@Component,@Service,@Repository. - I explained what functional interfaces are.
- The interviewer inquired about when to use an abstract class versus an interface.
- We talked about potential issues when multiple threads access a HashMap concurrently.
- I explained the use of beans in Spring Boot.
Round 2:
- I had to write a program to convert numerical time to words (e.g., '6:00' to 'six o'clock').
- A classic problem of designing a stack that can efficiently return its maximum element was given.
- We differentiated between
HashSet,LinkedHashSet, andTreeSet. - A scenario about the behavior of a
HashSetwhenequals()always returns true andhashCode()returns random values was discussed. - I explained the Singleton design pattern.
- Finally, we covered the differences between arrays and ArrayLists.
Overall, it was a thorough evaluation of my technical skills, covering a broad spectrum from fundamental DSA to advanced Java and Spring concepts.
Interview Questions (13)
Given an unsorted array of integers, find the length of the longest increasing subsequence (LIS).
Tell the minimum number of ways (or moves) to guess a 4-digit lock value correctly, starting from '0000'. This implies finding the shortest path in a state space, likely solvable with BFS.
Explain the differences and appropriate use cases for the Spring annotations @Component, @Service, and @Repository.
What is a functional interface in Java? Provide examples and explain its significance.
Explain the differences between an abstract class and an interface in Java, and discuss when to use each.
Describe the potential problems and race conditions that can occur when multiple threads concurrently access and modify a HashMap in Java.
Explain the concept and usage of 'beans' within the Spring Boot framework.
Write a program that takes a time in HH:MM format and converts it into words, following common English conventions. Examples include '6:00' to 'six o'clock', '6:10' to 'ten minutes past six', '6:15' to 'quarter past six', '6:30' to 'half past six', '6:45' to 'quarter to seven', '6:47' to 'thirteen minutes to seven', and '6:14' to 'fourteen minutes past six'.
Design a stack that supports push, pop, and getMax operations. The getMax operation should return the maximum element currently in the stack. All operations should aim for O(1) average time complexity.
Explain the differences between HashSet, LinkedHashSet, and TreeSet in Java, including their underlying data structures, order guarantees, and performance characteristics.
Describe the implications and potential issues if an object's equals() method always returns true, while its hashCode() method returns a random value, especially when used within a HashSet or as keys in a HashMap. How would this affect the size and retrieval behavior?
Explain the Singleton design pattern. Describe its purpose, common implementation strategies, and discuss its potential advantages and disadvantages or specific use cases.
Explain the key differences between Java arrays and ArrayLists, covering aspects such as fixed vs. dynamic size, type safety, underlying implementation, performance characteristics, and common use cases.