Java & Spring Interview Questions: What Really Happens Under the Hood There is a phase in every developer's career where you can use something without actually understanding what is happening underneath. You know how to use ConcurrentHashMap . You know what @Transactional does. You know that Spring injects dependencies. You know @SpringBootApplication starts your application. And then the interviewer asks: "Okay, but what actually happens internally?" Suddenly, knowing the syntax isn't enough. That is exactly what this blog is about. I'm going to break down some of the Java and Spring concepts that are frequently asked in interviews, but more importantly, I'll try to understand why they work the way they do . Let's start with one of my favourites. 1. ConcurrentHashMap in Java 8: What Actually Happens? Let's first establish the problem. A normal HashMap is not thread-safe. Imagine two threads doing this at the same time: map.put("A",...
All the widely diverging radii of the Universe meet at a common centre.It's not the question of how different we are but at what degree of differences we lie. Today science is evident that each body in this well diversified universe, arises from the one single source so, my friend we all are the streams coming out of one big ocean and will tend to converge in the same. It's just a drop out of that big ocean that I present in front of you fervently with the hope and gesture of unification.