Top 25 Topics and Resources to Crack Java Developer Interviews in 2024
Preparing for Java developer interviews? Here are essential topics and 500+ Java questions you can prepare with relevant books, courses, and articles
Hello guys, If you are aiming for Java developer interviews in 2024 but are confused about how to prepare for Java interviews then you have come to the right place. Earlier, I have shared the best books and courses to learn Java in 2024, and today, I am going to share some useful topics and resources to Crack Java developer interviews in 2024.
Java Interviews are a little bit different than traditional programming interviews on tech giants and product-based companies like Google, Amazon, Microsoft, or Facebook. First, even though it has questions from Data Structures and Algorithms like String, linked lists, or Array, you can still manage to clear Java interviews if you are not an expert on them.
The questions are a little bit easier and more practical than those companies. Another essential thing about Java interviews are questions based upon Java programming language and JDK API. Since Java is also an Object-oriented programming language, you will find lots of OOP questions there.
Since Java is primarily used as an application programming language, the focus is aligned accordingly with questions mostly focusing on API, Java concepts, and design patterns.
Also, Java interviews change a lot depending upon the candidate’s experience. For example, junior developers with 1 to 2 or 3 to 4 years of experience will see more questions on topics like Java fundamentals, API, and, data structure and algorithms.
More senior developers like Java programmers with 5 to 6 years of experience will find more questions on concurrent programming, Java concurrency API, JVM internals, GC tuning, and Java Performance.
So your preparation should be aligned with your experience and not just focused on common programming questions.
Also, Java EE interviews are totally different than core Java interviews because core Java interviews are mostly focused on core Java concepts like Concurrency, Collections, and JVM internals, while Java EE interviews are based upon a framework like JSF, Spring, Hibernate, and others.
The best way to prepare for Java interviews is to join a course like Java Interview Guide: 200+ Interview Questions and Answers, though there is no substitute for the experience you can still manage to sail through by carefully preparing for your Java interviews.
25+ Essential Topics for Core Java Interviews
As I told you, the importance of topics depends upon the candidate’s experience. I would ask more questions from Java fundamentals like String, Collections, equals() and hashcode and OOP concept to a fresher or Junior Java developer of 2 years experience, but those topics will be too trivial for Java developers of 4 to 5 years experience.
For those, I prefer to ask Concurrency, JVM internals, Garbage Collection, testing, and design patterns. Another thing that decides which topic you should prepare for your interview is the Job description.
Also, there is no better guide than the Job description to prepare for relevant topics.
For example, if you are going to work for a core Java multi-threading-based application, then you should prepare well for core Java topics like multithreading and concurrency, Java Collections, Generics, Enum, GC Algorithms, and JVM internals.
Similarly, if you are going to work for a Java Web Service application then preparing about REST and SOAP, XML, JSON, and other relevant topics.
For Java, web application developers, JSP, Servlet, Spring, and Hibernate are more critical than multi-threading and JVM internals. Similarly, for an Android developer, apart from knowledge of Java fundamentals, knowing Android API is more important.
Nevertheless, here is the list of topics I suggest to any Java developer who is serious about interviews.
- Java Fundamentals
- Object-Oriented Concepts (questions)
- Data Structure and Algorithms (questions)
- Multithreading, concurrency, and thread basics (questions)
- Date type conversion and fundamentals (questions)
- Garbage Collection (questions)
- Java Collections Framework (questions)
- Array (questions)
- String (questions)
- GOF Design Patterns (questions)
- SOLID design principles (questions)
- Abstract class and interface (questions)
- Java basics like equal and hashcode (questions)
- Generics and Enum (questions)
- Java IO and NIO (questions)
- Common Networking protocols (questions)
- Data structure and algorithm in Java (questions)
- Regular expressions
- JVM internals (questions)
- Java Best Practices
- JDBC (questions)
- Date, Time, and Calendar (questions)
- XML Processing in Java (questions)
- JUnit (questions)
- Programming questions (questions)
Apart from these topics, you could also take help from books like Java interview exposed and the Cracking the coding interview. These are great books written, especially from the interview perspective, and it will give you a good idea of what to expect in Java programming job interviews.
You will also find questions asked from various tech companies like Facebook, Google, and Investment banks like Barclays, Citi, Deutsche Bank, Morgan Stanley, and others.
For a more serious developer who wants to become an expert and not just focus on clearing an interview, I suggest you take a look at my 12 advanced Java books for experienced programmers article. It contains books for every important topic in Java.
And if you lack on some topic, you can always go back to the book you read or the course you followed to learn the Java-like The Complete Java MasterClass course on Udemy is a very comprehensive course and best for learning from scratch.
Best Courses and Books For Java Interviews
Recently I come across some excellent books to prepare for core Java and web developer interviews, these books focus more on core Java concepts like multi-threading, collections, Java fundamentals, etc., but also touch on web development concepts like Web service, Spring, Hibernate, JSP, Servlet, etc.
These books and courses are both cheap, will cost you less than $15 but give you enough practice and ideas to do well on your Java interviews.
Though nothing can beat the true experience and constant learning, if you are short of experience and have not been in touch with Java for more than a year, then you can use these books to prepare better for your Java interviews.
1. Java Interview Guide: 200+ Interview Questions and Answers
This is an excellent course to get an idea about Java interviews. It is very well organized and covers almost all the topics we have discussed here and probably more, like web services, spring, hibernate, JDBC, etc.
It is equally useful for both entry-level Java programmer and experienced Java developer interviews.
Here is the link to join this course — Java Interview Guide
2. Grokking the Java Interview (My Book)
This is my first book after 10 years of blogging and it contains 150 pages of interview questions, ideal if you have Java interviews in a couple of days or hours.
Even though the book is short, it touches on many essential areas of Java-like concurrency, collection, performance tuning, garbage collection, object-oriented programming, lambdas, stream, design patterns, generics, and other core Java concepts.
In short, if you are running out of time for your next Java interviews, this book will help you. You can also use my code friends20 to get 20% OFF on both my Java and Spring interview Book.
Here is the link to buy my eBook — Grokking the Java Interview
3. Java Multithreading for Senior Engineering Interviews
If you have an interview coming up, then I highly suggest you double down on concurrency and this is an excellent course to prepare for Multithreading and Concurrency Interview questions in Java.
Concurrency and Multithreading can be some of the most challenging topics brought up during most interviews, even for experienced developers. However, gaining mastery in concurrency will put you at a considerable advantage over other interviewees.
In this course, you’ll get a sneak peek at the most common types of concurrency interview questions like Producer-Consumer, Dining Philosopher, Reader-Writer, bounded buffer, and more, but you’ll also build a solid foundation of the basics as well as advanced concurrency concepts that will stick with you in your career and help you to perform at the highest level in interviews.
Here is the link to join this course — . Java Multithreading for Senior Engineering Interviews
If you don’t know Educative is another online learning platform that is gaining a lot of traction for its text-based, interactive learning courses. Reading is generally faster than watching and If you prefer reading text to watching videos then this is the platform to checkout.
It has some of the best courses to prepare for coding interviews like Grokking the Coding Interview: Patterns for Coding Questions (a unique course that will teach you 15 common coding patterns that can be used to solve 100+ Leetcode problems ) and Grokking the system design interview.
They also have a collection of 9 courses, a track called Ace the Java Interview which will get you up to speed on everything you need to know to nail your technical interviews in Java, covering topics from CS fundamentals to System Design. You’ll not just go over the theory, but get plenty of real practice along the way as well.
And, if you like the platform, I suggest you get an Educative subscription which costs $18 (50% discount now) monthly, completely worth it for a programmer and software engineers where continuous learning is required.
That’s all about how to prepare for Java interviews guys. The Java ecosystem is vast and but depending upon Job description, you can further narrow down your preparation areas, if you are going for core Java interviews, then you should focus more on core java concepts, like, multi-threading, collections, and JVM internals.
Similarly, if you are going for a Java web developer interview, then you should focus more on the web development aspect, e.g., security, MVC frameworks like Spring, Struts, and ORM frameworks like Hibernate and iBatis.
Further Learning
The Complete Java MasterClass
Data Structures and Algorithms: Deep Dive Using Java
Algorithms and Data Structures — Part 1 and 2
Grokking the Java Interview Book
Grokking the Spring Boot Interview Book
Other Java Interview resources for you
- 133 Java Interview Questions from the last 5 years (list)
- 15 Data Structure and Algorithm Interview Questions (list)
- 10 Spring Framework Interview Questions (list)
- 20 Hibernate Framework Interview Questions with Answers (list)
- 50 Java Concurrency Interview Questions (list)
- 25 Java Collection Interview Questions (list)
- 10 RESTful Web Service Interview Questions for Java developers (list)
- 10 Data Structure and Algorithms Courses for Interviews (courses)
- 50+ Data Structure and Algorithm Questions (questions)
- 20 Spring MVC Interview Questions for Java Developers (questions)
- 20 Spring and REST Interview Questions for Java Programmers (questions)
Thanks for reading this article, if you have found this article useful and worth sharing, then please share it with your friends and colleagues. If you have any suggestions or feedback or if you want to share any of your personal tips which helped you to do well in the Java interview, then please drop a comment.
P. S. — If you are new to the Java development world and need a comprehensive course to both learn Java and prepare for an interview then I recommend you to check out The Complete Java MasterClass course by Tim Buchalaka on Udemy. This 80+ hour course is the most comprehensive Java course on the internet.
