📘 Java Memory & Core Concepts
What is Meta Space in Java?
What if you don’t synchronize a method in Java?
How was the internal implementation of Java HashMap changed with JDK 1.8?
Is Java Interpreted or a Compiled Language?
What if you return constant hash code of 1 from hashCode method and don’t override equals()?
Synchronized member method versus static synchronized method — can two threads access different synchronized methods simultaneously?
Follow-up: If you have one instance and one static synchronized method, can two different threads execute these methods simultaneously?
Explain String constant pool.
How are Streams different from Collections?
📘 Optional & Stream API
Describe the use of Optional in Java.
Describe the difference between map, flatMap and reduce in Stream.
Understanding Reduce — how does reduce work in streams?
What happens if you call Optional.get() on an empty Optional?
Why should we avoid nested Optionals?
How should Optional be handled properly in Streams?
📘 CompletableFuture & Concurrency
How do you make concurrent API calls in Java?
How do you process data in an asynchronous manner in Java?
How do you combine results from multiple sources using CompletableFuture?
How do you implement timeout using CompletableFuture?
How to implement non-blocking computation using CompletableFuture?
Could you provide an example of parallel data processing?
Can you rewrite parallel processing using thenAcceptAsync and explain the difference?
How do you aggregate responses from different APIs?
How do you use parallelStream with Future to achieve asynchronous API calls?
How do you use a custom thread pool with CompletableFuture?
📘 HTTP & Application Architecture
How does HTTP caching work for static resources?
How does handling of stale resources work in HTTP caching?
Explain the Thread-Per-Request model.
How does Tomcat manage web requests?
What are alternatives to the Thread-Per-Request model?
📘 Modern Java Features
What is mapMulti in Java?
Why did Java introduce default methods?
Explain Class Loading in Java.
What is the difference between checked and unchecked exceptions?
Explain Metaspace in Java.
📘 Threads & Synchronization
What is a Thread in Java?
What are the different Thread States?
What is a fully synchronized object in Java?
📘 Core Java Design & Best Practices
What are obsolete references and how can they cause memory leaks?
Why must any class that overrides equals() also override hashCode()?
What will happen if hashCode() is not overridden in a HashMap key class?
Which is better and why?
String s = new String("Core Java");String s = "Core Java";
Why should expensive objects like Pattern be cached?
What problem does try-with-resources solve?
Why was java.time introduced? What were the problems with Date and Calendar?
📘 Java Evolution & Architecture
What were the limitations of java.util.Date?
What were the limitations of Calendar?
Why is DateFormat not thread-safe?
Why was Joda-Time introduced before Java 8?
How does Spring MVC request processing work internally?
I am working on a guide to help all sorts of developers , please support me if you want this to be successful.
Thanks for Subscribing.