Top 70 Java Interview Questions for Junior Developers [1 to 2 Years Experienced]
Java Developer Interviews are very different than traditional software developer interviews. You can clear a Java interview without even writing a single line of code, Yes, this is true, you can become a Java developer without someone asking you to write a function in a Java interview. Though it’s not the case everywhere and many companies are increasingly including a coding test in their Java developer interview process, but there are many companies and start-ups where you can get a Java job without writing a single line of code. All you need to do is learn those popular Java questions, which have been asked for ages, and mostly test whether a candidate is familiar with essential Java concepts or not like abstract class and interface.
This is great for candidates which are looking for their first job and doesn’t have much real-world coding experience, but sometimes this style of the interview can cost you good developers who are not good at interviews.
Someone, who knows how to structure a complex program, knows how to model their class and objects, can write good, robust code but fail to answer questions like, Why String is Immutable? or How HashMap works in Java?
Since I have gone through a lot of such interviews and even conducted a couple of them, I thought to compile a list of some of the most frequently asked Java interview questions, covering key topics like design patterns, design principles, OOP, JVM internals, Garbage collection, multithreading, generics and collections, XML parsing and others.
This list is a collection of such questions. I have not answered them right here because I have already answered them in their individual post in this blog, you can visit the answer link to see the answer.
Btw, if you are new to Java then I highly recommend you to go through a comprehensive Java course like The Complete Java Master Class before attempting these questions. You will save a lot of time and will be better prepared for the interview. While you can learn a lot of useful Java concepts using these questions, it’s still better to join a well-structured course. You can later revisit this list for quick revision.
70+ Java Interview Questions with Answers Junior Developers
The sole purpose is to conduct mock Java interviews by yourself. You can use this list to do last-minute revisions. Since answers are not provided, you can try answering them and if you can then you are ready to take on any telephonic round of Java interview or face-to-face round which doesn’t involve coding.
31) Create an Iterator filtering framework: an IObjectTest interface with a single boolean test(Object method and an Iterator sub-class which is initialized with another Iterator and an IObjectTest instance. Your iterator will then allow iteration over the original, but skipping any objects which don’t pass the test. Create a simple unit test for this framework.
32) Difference between Abstract class and Interface — given a situation what would you choose between abstract class and interface? (answer)
36) Explain about HashMap (methods in HashMap and the project in which we have used the HashMap more about equals() and hashCode() (answer)
These questions are good enough to revise many essential Java concepts but if you want more thorough Java interview preparation then you can also check out Ace the Java Interview track on Educative, a text-based, interactive learning platform, best for coding interviews.
That’s all about some common Java Programming concept-based Interview questions for beginners and junior developers with 1 to 2 years of experience. While this list is not comprehensive, it does touch on many important concepts which every Java programmer should know. By going through these interview questions and answers you can quickly revise those essential concepts and get ready for your telephonic or face-to-face interview.
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Thanks for reading this article so far. If you like these Java concepts interview questions for beginners then please share them with your friends and colleagues. If you have any questions or feedback then please drop a note.
P. S. — If you can’t answer these basic Java questions and you should join a comprehensive Java course to revise essential concepts. If you need a recommendation then I highly suggest going for The Complete Java Master Class, an 80-hour long course on Udemy which you can buy for just $10 on Udemy sales.