How I Learned Java in Depth by preparing for Java Technical Interviews
Tags: java, coding, webdev, career
Published: 2023-04-04 10:41:18

This is based on my personal experience. How I Learned Java in Depth while preparing for Java Developer Technical interviews. I will share my Takeaways from it. It helped me to gain more knowledge and Triple my Salary in less time. Since the demand for Java professionals is huge in the Market.



I assume my readers are mostly Java Developer professionals or developers, Who are seeking to expand their knowledge base so that they can excel in their current or next role.

How My Java Interview prep helped me to learn more in depth

When I started working as a Junior Java dev back in my initial days, early in my career. Whenever I was working on a task, I used to do a lot of googling for every coding logic that I can find over the internet. I was more of a stack overflow engineer.

Having a mentor in the early days is a very fortunate thing to have. They can guide you correctly rather than spending more time googling and completing the task. But I was not that lucky on that front.

When I started hunting for my next job, I got a lot of rejections and humiliation in technical rounds, because whatever I have learned was superficial only.

After a few months of preparation and facing the interviews, I got to know the value of five things that makes the difference in the technical interview and that was,

Reading Java API documentation helped to understand the underlying API of JDK. like how they internally work, and what time and space complexities they have when we use them in code.
Reading good books on Java like Head First Java and Effective java built my Object-oriented programming basics plus added a base to my Java knowledge. I assure you these books will definitely lay a strong foundation for your profile.

3. When we work on a project we don't pay attention to what is the best practices we should be following while writing code. we were solely focusing on getting the job done. We always write code in a brute force way and not in an optimized way if you working for NON-FAANG companies. In a coding interview, I have been always asked about the optimized code.

So solving coding puzzles/problems on leet-code and hacker rank helped me to write better code.

4. Design patterns and System design questions were asked most of the time. While facing the interview I got to know the importance of them and I have added them to my knowledge base as well

5. Importance of Unit testing, sometimes interviewers test your unit testing knowledge. I had to learn the Junit framework in depth because of that.

Topics which i learned in Depth while preparing java technical interview

Core Java API (Collection framework, Stream, Java Lang Package, Java Util Package, Java Time Package, Java IO Package, Java net Package, Java SQL Package)
Design patterns (Builder, factory, proxy, adaptor, facade, observer design patterns)with examples.
SOLID Design principles with their practical use in coding.
Read Clean code and clean coder of uncle bob which added clean coding habits (fewer WTFs in my Code reviews after that :))
Spring Framework, Hibernate framework, and JPA in depth
A unit testing framework that I have learned was, J-UNIT, MOCKITO, and POWER MOCK. which helped to clear the code coverage criteria in my pipeline.
Unless I have given the interviews I would not have studied the above topics in depth which are very important as a developer.

After learning all of those in a theoretical and practical way I was able to clear more technical rounds and I was able to triple my salary in less time span. also, I was recognized in my next role as a Strong technical resource.

One of the comments that my manager gave me in my appraisal was.

**“Ajay is Technically very good and he provides quality code in a timely manner”.**
That was encouraging to me, how your preparation also makes you a good developer. I hope this helps my fellow readers in their path.

_If you are preparing for a Java Springboot microservice interview look no further to add the below book to your prep material, it has 250+ interview questions and answers asked in an interview._

[Guide To Clear Java Developer Interview:
](https://rathodajay10.gumroad.com/l/whbqi)
Gumroad Link — [Gumroad](https://rathodajay10.gumroad.com/l/whbqi)

Amazon Link — [Amazon](https://www.amazon.in/dp/B0BZJKLPTM)

Follow me: [LinkedIn](https://www.linkedin.com/in/ajay-rathod-b3913861/) | [Twitter ](https://twitter.com/ajtheory)| [Medium](https://medium.com/@rathod-ajay)