Java developer interview questions: 23 to prepare for
Each question says why it is likely to come up, from what today’s 359 open Java developer postings ask for, and what a good answer shows. Prepare a real example for each, then practise it with the interview answer builder.
Updated Nov 15, 2026, from that day’s open postings.
Practise out loudThe page reads each question aloud and checks your answer. This site keeps nothing.
- Questions to prepare
- 23
- Open Java developer jobs today
- 359
- Postings read in full
- 91
- Median advertised pay
- $200K
Questions about the skills Java developer postings name
Walk me through a recent project where you used SQL. What did you do yourself?
34% of today’s 359 open Java developer postings name SQL.
A good answer shows: Your own hands-on part, the choices you made and a number for the result.
Sample answer: “In my last role I rebuilt the order service in Python, cutting median response time from 480 ms to 190 ms at the same traffic. I did that part myself: I chose how to do it, checked the result and explained it to the team.” Then say what you would do differently.
What is a mistake people often make with Agile, and how do you avoid it?
31% of today’s 359 open Java developer postings name Agile.
A good answer shows: That you have used it long enough to know where it goes wrong.
Sample answer: “In my last role I rebuilt the order service in Python, cutting median response time from 480 ms to 190 ms at the same traffic. I did that part myself: I chose how to do it, checked the result and explained it to the team.” Then say what you would do differently.
How would you explain Jira to someone who has never used it?
7% of today’s 359 open Java developer postings name Jira.
A good answer shows: That you understand it well enough to make it simple.
Sample answer: “In my last role I rebuilt the order service in Python, cutting median response time from 480 ms to 190 ms at the same traffic. I did that part myself: I chose how to do it, checked the result and explained it to the team.” Then say what you would do differently.
Technical Java developer interview questions and answers
Which clause keeps only the rows that meet a condition before any grouping happens?
A SQL question (34% of today’s postings name SQL). More in the SQL skill test.
Answer: WHERE. WHERE filters rows first. HAVING filters groups after GROUP BY.
What does an INNER JOIN between customers and orders return?
A SQL question (34% of today’s postings name SQL). More in the SQL skill test.
Answer: Only customers that have at least one matching order. An inner join keeps pairs that match on both sides. A LEFT JOIN is the one that keeps customers without orders.
You need the number of orders for each customer. Which query does it?
A SQL question (34% of today’s postings name SQL). More in the SQL skill test.
Answer: SELECT customer_id, COUNT(*) FROM orders GROUP BY customer_id. GROUP BY makes one row per customer, and COUNT(*) counts the rows inside each group.
What is the result of comparing a value with NULL using = (for example, price = NULL)?
A SQL question (34% of today’s postings name SQL). More in the SQL skill test.
Answer: Unknown, so the row is never returned. NULL means “no known value”. Any comparison with = gives unknown. Write IS NULL to find empty values.
What is a container?
A Docker question (28% of today’s postings name Docker). More in the Docker skill test.
Answer: A running instance of an image, isolated from the rest of the machine. A container shares the machine’s kernel, so it starts in seconds and uses much less than a full virtual machine.
What is an image?
A Docker question (28% of today’s postings name Docker). More in the Docker skill test.
Answer: A read-only template from which containers are started. You build an image once and start as many containers from it as you like.
Which file describes how to build an image?
A Docker question (28% of today’s postings name Docker). More in the Docker skill test.
Answer: Dockerfile. A Dockerfile is a list of steps: start from a base image, copy the code, install what is needed.
What does docker ps show?
A Docker question (28% of today’s postings name Docker). More in the Docker skill test.
Answer: The running containers. docker ps -a also lists the stopped ones; docker images lists the images.
Questions about how you work
Tell me about something you owned from the first idea to the result.
58% of today’s 91 open Java developer postings with a full description ask for ownership or end-to-end work.
A good answer shows: That you saw it through when it got hard, with a number for the result.
Tell me about a time a rule or regulation slowed your work down. What did you do?
45% of today’s 91 open Java developer postings with a full description mention compliance or regulation.
A good answer shows: That you followed it and still delivered, not that you went around it.
How do you work with a team that is mostly in other time zones?
42% of today’s 91 open Java developer postings with a full description mention working across time zones.
A good answer shows: Clear written updates, the overlap hours you keep and decisions that do not wait for a call.
Describe a project you delivered with people from other teams. What was your part?
26% of today’s 91 open Java developer postings with a full description ask for work across teams.
A good answer shows: Your own part, how you kept the teams in step and the result.
Tell me about a time you had to win over people outside your team who disagreed with you.
23% of today’s 91 open Java developer postings with a full description mention stakeholders.
A good answer shows: Who they were, what each side wanted, what you did to reach agreement and how it ended.
Have you helped someone else get better at their work? What did you do?
20% of today’s 91 open Java developer postings with a full description mention mentoring.
A good answer shows: A specific person and skill, how you taught it and how they did afterwards.
Questions almost every interview has
Tell me about yourself.
Almost every interview opens with it.
A good answer shows: Under a minute: your current work as a Java developer, one result with a number and why this job is the next step. Not your whole resume.
Why do you want to work here?
It tests whether you read about the company.
A good answer shows: Something specific: a product, a goal from the posting or a problem you can help with.
Why are you leaving your current job?
It checks for problems you might bring along.
A good answer shows: What you are moving towards, said briefly, with no criticism of your employer.
What are your salary expectations?
Only 26% of today’s Java developer postings state pay, so be ready to name a figure.
A good answer shows: A range you can defend. Today’s 65 Java developer postings that state a yearly US-dollar range advertise a median of $200K; the middle half $179K to $200K. Ask for their range first if you can.
What is one of your weaknesses?
A classic, still asked.
A good answer shows: A real weakness that does not block this job, and what you do about it.
Do you have any questions for us?
The last question of almost every interview.
A good answer shows: Two or three questions you prepared; the list below has some.
Questions to ask them
- What would make someone in this role successful in the first six months?
- It shows you think about results, and the answer tells you what the job really is.
- Why is this role open?
- A new role, growth or someone leaving: each tells you something different.
- What is the pay range for this role?
- Only 26% of today’s Java developer postings state one; asking is normal.
- How will my work be measured, and how often will we review it?
- You learn what matters to your manager before you start.
- What are the next steps, and when will you decide?
- You know when to follow up, and you can plan around other offers.
Questions about a Java developer interview
- What questions are asked in a Java developer interview?
- Questions about the skills the postings name (SQL, Agile, Jira), about how you work (end-to-end ownership, compliance and regulation, time zones) and the questions almost every interview has, such as “Tell me about yourself” and your salary expectations.
- How should I answer Java developer interview questions?
- With a real example: the situation, what you had to do, what you did yourself and the result, with a number. This is the STAR method; aim for 60 to 90 seconds an answer.
- How do I prepare for a Java developer interview?
- Prepare three real stories with a number each (a result, a problem you solved, work with other people), practise them out loud for 60 to 90 seconds, and revise the skills the postings name most: SQL, Agile, Jira. Read the posting again the day before: the duties it lists are what they will ask about.
- Is a Java developer interview hard?
- It depends on the level: today’s Java developer postings ask for 5 years of experience at the median. Most interviews mix questions about the skills in the posting with questions about how you work; the technical part is easier with a real example ready for each skill.
- What salary should I ask for as a Java developer?
- Today’s 65 Java developer postings that state a yearly US-dollar range advertise a median of $200K. Adjust for your experience and the country, and ask for their range first.
Prepare with
Interview answer builder
Turn an example into a 60 to 90 second answer, with checks for a number and for “I”.
The Java developer resume example
The results interviewers ask about, written as resume lines.
Thank-you email
Send it on the day of the interview, written from four fields.
359 open Java developer jobs
Read from employers’ own careers pages every hour.
Everything about Java developer work
Counted from the open postings on Nov 15, 2026, read from employers’ own careers pages and recounted on every update. The questions are ours; no employer’s interview is copied here.