Java Developer Interviews

Java Developer Interview Questions

In your interview for a java developer position, be prepared to answer technical questions that test your understanding of Java basics. Interviewers may also ask open-ended questions to assess your coding and problem-solving abilities. Prepare for non-technical questions that focus on time management, interpersonal communication, and work ethic.

Top Java Developer Interview Questions & How to Answer

Question 1

Question #1: What is the difference between HashTable and HashMap in Java?

How to answer
How to answer: Interviewers use technical questions to assess your formal training and understanding of the Java programming language. Use your answer to demonstrate your communication skills. Even if you have been coding for some time, it can be helpful to review Java basics before your interview.
Question 2

Question #2: Write a program to determine if 243 is an Armstrong number.

How to answer
How to answer: Interviewers use open-ended questions to test your coding skills. This question allows the employer to assess your ability to solve a problem using a Java algorithm. Explain your thinking process as you use a code editor or whiteboard to solve the problem.
Question 3

Question #3: How do you produce quality code when you have several Java projects to complete at once?

How to answer
How to answer: Java developers often juggle multiple projects at the same time. Interviewers use questions such as this to test your time management and organizational skills. Employers are also trying to assess your commitment to quality work. If you have experience as a developer, include examples from your work history that demonstrate high-quality work and effective time management.

30,885 java developer interview questions shared by candidates

1. OOps concepts with examples. 2. Write a java program to find the first duplicate in an array. 3. Write a java program to print the occurrences of each character. 4. Explain the approach to print middle element in a linked list. 5. Given a string str = "hfjsk6485lop", sort the string and print the characters first and print digits last. 6. Find a missing a element in an array. 7. Collection framework hierarchy. 8. Difference between abstract class and interface. 9. What is association and aggregation . 10. some code snippets to answer. 11. Internal working of a hash map, what is the case if two elements hash code is same. 12. What are the challenges that you faced in your projects how you have handled them. 13. Difference between string, stringBuffer, String builder. 14. Difference between final, finally, finalize. 15. Difference between Exception and Error. 16. Can you throw custom exception with Error Object. 17. Exception handling hierarchy.
avatar

Software Engineer - Java Developer

Interviewed at Siemens

4.1
Jul 9, 2021

1. OOps concepts with examples. 2. Write a java program to find the first duplicate in an array. 3. Write a java program to print the occurrences of each character. 4. Explain the approach to print middle element in a linked list. 5. Given a string str = "hfjsk6485lop", sort the string and print the characters first and print digits last. 6. Find a missing a element in an array. 7. Collection framework hierarchy. 8. Difference between abstract class and interface. 9. What is association and aggregation . 10. some code snippets to answer. 11. Internal working of a hash map, what is the case if two elements hash code is same. 12. What are the challenges that you faced in your projects how you have handled them. 13. Difference between string, stringBuffer, String builder. 14. Difference between final, finally, finalize. 15. Difference between Exception and Error. 16. Can you throw custom exception with Error Object. 17. Exception handling hierarchy.

Q1) Write simple java code for ,whether given string have character "i" ,using stream API only. Ex: If input is "hello" word, output will be false, as the word doesn't have letter "i". Q2) what is volatile keyword is used for? Q3)explain oops concepts? Q4)why java doesn't support multiple inheritance, what happens if we try to implement? can you explain with some example ? Q5)what is multi threading? Do you know about executor ? Q6)what is REST? Q7)When we are opening a google page, which type of request it is?GET or POST or other requests? Q8)how Requests are mapping with servlets in SPRING MVC? can you explain? Q9)Why spring boot s required,when we have many spring components already?Advanatages of Springboot? Q10)what is Springboot profiling concept? Q11)What are the things you write or configure,in your spring boot application,related to tomcat? Q12)what collections you used in your project?explain How hashmap buckets internally works? Q13)DIfference between HTTP and HTTPS? Q14)What type of errorcodes you get genearlly, when you access a REST webservice using browser? etc
avatar

Java Developer

Interviewed at Synechron

4.1
Jun 7, 2022

Q1) Write simple java code for ,whether given string have character "i" ,using stream API only. Ex: If input is "hello" word, output will be false, as the word doesn't have letter "i". Q2) what is volatile keyword is used for? Q3)explain oops concepts? Q4)why java doesn't support multiple inheritance, what happens if we try to implement? can you explain with some example ? Q5)what is multi threading? Do you know about executor ? Q6)what is REST? Q7)When we are opening a google page, which type of request it is?GET or POST or other requests? Q8)how Requests are mapping with servlets in SPRING MVC? can you explain? Q9)Why spring boot s required,when we have many spring components already?Advanatages of Springboot? Q10)what is Springboot profiling concept? Q11)What are the things you write or configure,in your spring boot application,related to tomcat? Q12)what collections you used in your project?explain How hashmap buckets internally works? Q13)DIfference between HTTP and HTTPS? Q14)What type of errorcodes you get genearlly, when you access a REST webservice using browser? etc

Viewing 1601 - 1610 interview questions

Glassdoor has 30,885 interview questions and reports from Java developer interviews. Prepare for your interview. Get hired. Love your job.