Asking the right Java interview questions can improve your talent acquisition strategy and ensure you hire the most creative, skilled, and passionate web developers.
With more than 9 million professionals using Java, it is one of the most popular programming languages available. However, when so many individuals proclaim their expertise, it can be difficult to differentiate the skilled from the imposters.
The following Java interview questions can guide you in hiring people with the expertise and experience necessary to do the job well:
- Discuss the differences and similarities between an abstract class and an interface.
Not only should the developer have a strong understanding of the differences and similarities between an abstract class and an interface, but they should also know when to use each one.
- How do you make Java methods virtual?
This question will likely confuse an inexperienced developer, which is precisely why you should ask it. The correct answer is that Java methods are automatically defined as virtual, so there is no need to make them such.
- Tell me the difference between abstraction and encapsulation.
This can be an effective question to ask as many developers tend to confuse abstraction and encapsulation. While encapsulation hides the data, abstraction hides the implementation details and lets you focus on what the object does. If your candidate can answer this question properly, it demonstrates a strong understanding of both concepts.
- Why is the Java main() function defined as static?
An experienced developer will understand why Java programmers use this function so often. They will also be able to tell you that the main() function is static so that it can be called without creating an instance.
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- What does type erasure mean?
This is something that most novice developers do not know. The answer: type erasure means that the runtime has no knowledge of the types of generic objects.
- What is the base class for error and exception?
Again, most people don’t know the answer to this question, so asking it can help you identify an experienced developer. The answer: Throwable is the super class or base class for exception and error.
- What is the difference between throw and throws?
Good developers will know the difference between the two. While throw is used to throw an exception, throws is used to declare an exception.
- How do you implement a HashTable with basic Java constructs?
This question is important because it tests the candidate’s comprehension of Java fundamentals and understanding of data structure. A correct answer also demonstrates strong logic skills.
Finding a skilled, experienced and trustworthy developer to join your team is no easy feat. Though you will want to take additional qualifications into account as well – such as flexibility, personality and cultural fit – these Java interview questions will either confirm or dispel that the candidate can handle the technical aspects of the job.
If you’re looking to hire qualified developers, Sparks Group offers staffing and recruiting services tailored to the needs of IT firms and IT government contractors.