Feb 5, 2023


Java Interview Questions

When you're ready to hire someone new for your team, it's important to think about what questions you should ask during the interview. You want to focus on the questions that are most relevant for your team and role you're hiring for, so you can understand how candidates will use their skills and experience to contribute to your company.

Look for someone with different areas of expertise from your own—this way, you can supercharge your team and get more done!

What Are the Questions Asked in Java Interview?

Sitting someone down for an interview is often stressful and difficult, but with some preparation ahead of time you can make it much easier to find the right person for your team.

We’ve put together a list of Java interview questions that will help you evaluate candidates and determine whether they’re a good fit for your team.

Below are the Java interview questions we've had the most success with over the years. They're meant to be used as a guide. You can add your own questions and tweak them as needed.

We've divided them into three sections:

  • Core

  • Collections

  • Concurrency


  • Describe the access modifiers in Java.

  • What can you say about local variable in java?

  • When we method can we change access modifier, return type?

  • Describe the work unit try-catch-finally.

  • What is the Error?

  • How to create unchecked Exception?

  • What is checked and unchecked Exception?

  • Describe the Exception hierarchyWhat words final, finally and finalize, are used for?

  • Describe the method Object.finalize().

  • What is default constructor?

  • Rules for overriding Object.clone().

  • Rules for overriding Object.hashCode().

  • Rules for overriding Object.equals().

  • Which methods have class Object? Which methods can be overridden, and what can’t?

  • How do you deliver the variables in the methods by value or by reference?

  • What are Generics?

  • What is autoboxing?

  • What types of nested classes you know? 

  • What are they used for?

  • What is the difference between abstract class and interface? When would you use an abstract class and when interface?

  • What is the difference between StringBuilder and StringBuffer?

  • What is the difference between a constructor and a method?


  • What is the difference between ArrayList and LinkedList? In which cases it is better to use the first, and in which the second?

  • What is the difference between HashMap and Hashtable?

  • What is the difference between the ArrayList and Vector?

  • Explained to the differences between the HashSet, LinkedHashSet, TreeSet.

  • What's the synchronized version of a HashMap?


  • How I can create a thread?What is synchronization in Java?

  • What do the methods wait and notify / notifyAll are used for?

  • What distinguishes the work of the method wait with a parameter and wait without parameter?

  • How the method Thread.yield() works ? What is the difference between Thread.sleep() and Thread.yield() methods?

  • How the method Thread.join() works?

  • What is a dead lock?

  • How to kill thread correctly?

  • What keyword volatile mean?

Interview Scorecard Templates by InterviewTime

To save everyone's time, InterviewTime has created a list of templates available for you to use as-is or as inspiration for creating your own interview scorecard template based on what information will be useful for hiring in your company!

To learn more about scorecards, check out our article - Interview scorecard: pros & cons.

Keep all interview assets in one place. Make your interview process consistent.