Java Prep

1. Understand the Basics Thoroughly

First things first, ensure you have a solid grasp of Java's core concepts, including data types, control structures, object-oriented programming principles, SOLID principles, and exception handling. Interviewers often start with fundamental questions, so be prepared.

2. Data Structures and Algorithms

Java developers are expected to be comfortable with data structures and algorithms. Brush up on topics like arrays, linked lists, stacks, queues, and basic sorting and searching algorithms. Practice solving coding challenges to enhance your problem-solving skills.

3. Object-Oriented Programming (OOP)

Java is an object-oriented language, so expect questions about OOP principles like encapsulation, inheritance, and polymorphism. Be ready to explain how you've applied these concepts in your projects.

4. Collections Framework

Know the Java Collections Framework inside out. Understand when to use ArrayList, LinkedList, HashSet, and other collection classes. Discuss their time complexity and trade-offs. Almost, in each interview, there would be at least one question about the collections.

5. Exception Handling

Java's robust exception handling is crucial. Be prepared to explain how you handle exceptions in your code and discuss checked and unchecked exceptions. The Java core exception hierarchy is important to know. The parent of all Exception classes and errors is Throwable. Consider that error is different from exception. I’ll write an article about it soon.

6. Multithreading

Multithreading is a common topic in Java interviews. Familiarize yourself with thread creation, synchronization, and deadlock prevention techniques. Even a junior developer should be aware of how to create new threads or run a specific method in a separate thread. I also suggest to study about reactive programming a bit. There are wonderful tools, classes, and interfaces such as Future, and CompletableFuture that can help you achieve multithreading and reactive programming.

7. Java Virtual Machine (JVM)

Understand the role of the JVM in running Java applications. Know about memory management, garbage collection, and JVM tuning. Garbage collection is very important to know. How garbage collection detect that there is no reference to the object in the heap?!

8. Design Patterns

Be aware of common design patterns like Singleton, Factory, and Observer. Discuss their usage and benefits in real-world scenarios. Knowing the design pattern itself doesn’t have value added, but knowing where to use them can be your sword in interviews!

9. Database Connectivity

If your role involves database interaction, be ready to discuss SQL queries and your experience with JDBC or JPA (Java Persistence API). At least working with an ORM to increase your knowledge about it.

10. Frameworks and Tools

If you have experience with Java frameworks like Spring or tools like Maven or Gradle, be prepared to showcase your knowledge and how you've used them in projects.

11. Practice Coding Questions

Practice coding questions on platforms like LeetCode or HackerRank. Solving real-world problems in Java can help you build confidence and improve your coding skills.