Core Java Interview Questions

Most of hiring experts is going to say that Java is one of the most in-demand tech skills, today. And they are 100% right in this manner. Getting such a job is often hard even for those who have been reading tons of books in this field, going to numbers of job interviews and aced every single course. The patterns of core Java interview questions is changing with every few years, making the potential employees hard to keep up with the patterns of questions they may stumble upon while being interviewed by their future employers. Many people think that to present themselves as Java specialists during a job interview, boils down to answering the most difficult questions. However, in most cases the simplest questions are the ones that determine the future of such a person in one of those well-developed companies.

Every single time when another version of Java platform is being released, the API grows, and with it also grows the number of questions you may encounter while fighting even for a typical software development job. So, be prepared that when you put Java on your resume, there is a big chance you will probably have to give an answer to a question in the range from the first to the last version of Java release. And that is why, no matter if you are fresh out of school or you already have experience in Java programming, your main goal should be focused on how to properly prepare for such interview.

How to prepare for an


The first step to get ready for the battle is to have a perfectly created resume. Be sure to list all your schools, courses, achievements, past jobs, skills etc. Do not lie and do not hyperbolize. Remember; everything you list on this piece of paper, you can be asked about. So, be honest in every single aspect. Even, when you are interested in some high technology field, but you do not know much about it u2013 it would be best to keep that to yourself. Because even the simplest question may then be a nail to the coffin for your entire interview. When opting for a job as a Java developer, you should expect different types of questions on Java fundamentals (strings, autoboxing, exceptions etc.), arrays (their advatages and disadvantages), puzzles, maps (HashMap, Hashtable etc.), collections (Vector, Iterator), and object oriented process (encapsulation, polymorphism, inheritance and abstraction).

There may be moments when someone will ask you to write a code. In such situation be sure to focus properly and follow basic standards. And remember to always write it with good indentation, and do not tell that you forgot about this or that. No one expects from you to remember all, but be sure your basics are always covered. Also, while writing a code, be sure you explain everything you are doing. Write a couple of sentences on the subject, and it should do the trick. Your future employer may also ask you to prepare an architectural diagram of your project, so be sure you can explain everything in the diagram you have just drawn.

Don’t hesitate to brag when asked about your greatest achievements. This is the part where you can present yourself from your best side, and make sure your answer is interesting and captivating. Mention a few situations in which your skills helped you, leading you to extraordinary places.

The last part of the interview is often based on what kind of questions you have for your potential employer. You can, of course, say there are none. However, it is always better to ask some smart questions that are going to show you really care for the position you are aiming for.

Another good form of preparation for a core JAVA interview questions are books. There are many types available on today’s market. So, make sure you choose the ones that will help you to get the job you want. For example, if your goal is to work for a core Java multi-threading based application, then you should opt for books that provide information on such topics as multi-threading and concurrency, GC Algorithms, JVM internals, Enum, and Java Collections. Don’t waste your time on getting information you will not need.

Try to find different types of quizzes, interview patterns, and questions that may be asked while interviewed by your future boss. Ace them all, and make them stick to your memory, constantly repeating them for yourself as your personal mantra. This way, when asked about them, you will be singing during your interview.

Examples of

CORE Java interview questions

There are hundreds of questions that can be asked about Java, so make sure to narrow them only to those which hark back to the particular type of job you are interested in.

One of the most typical ones are:

  • What JVM is?
  • What kind of method you use to keep your code well-organized?
  • Which Java frameworks have you been working with and why?
  • What is the difference between StringBuffer and String?
  • However, you can also get questions as those:
  • Why is multiple inheritances not supported in Java?
  • How to override a private or static method in Java?
  • Can you write Java program to create a deadlock and fix it?
  • How can you mark an array volatile in Java?

Do not forget to listen very closely to the questions your future employer is asking you. And make sure you understand them properly. Be confident in your answer, if you are 100% you are right. But if you are not, do not force this confidence on yourself, because the employer will know you are wrong. And then he or she won’t be sure if your confidence – related to the core java interview questions you answered right – results from your knowledge or its lack of.

Preparing for a core Java interview questions is a quite difficult thing to do. There are many different aspects to cover. That is why, you should be well-organized and eliminate the questions you will probably not get. Otherwise, it can all overwhelm you very quickly. And before the interview, try to relax, take a few deep breaths, be presentable, and confident in your skills.