As a Software Engineer at Dollar General, you will play a pivotal role in shaping the technology that powers one of the largest discount retailers in the United States. This role is not just about writing code; it involves designing, developing, and maintaining software solutions that enhance the shopping experience for millions of customers and streamline operations across the organization. You will contribute to various projects that impact our products, services, and internal processes, enabling Dollar General to maintain its competitive edge in a fast-evolving market. The work you do as a Software Engineer will directly influence customer engagement, inventory management, and data analytics, contributing to our mission of serving our communities and providing value to our customers. You will be part of a lean, agile team that emphasizes collaboration and innovation, working on complex systems that require a deep understanding of software architecture and user experience. The complexity and scale of our systems present unique challenges that make this role both critical and exciting. Expect to engage with a variety of technologies and frameworks, contributing to projects that touch on e-commerce, mobile applications, and internal tools. Your contributions will help drive operational efficiency and improve customer satisfaction, making your role integral to the overall success of Dollar General.
Initial Screening
reportedThe process begins with an initial screening to assess candidate qualifications.
What to demonstrate
- The process begins with an initial screening to assess candidate qualifications
- Depth in Java
How to prepare
- Be able to walk your CV end to end in two minutes, and say why this company specifically.
- Have your salary expectations, notice period and location constraints ready, and ask for the rest of the loop in writing.
Technical Interviews
reportedCandidates participate in technical interviews focusing on their resume and past experiences.
What to demonstrate
- Candidates participate in technical interviews focusing on their resume and past experiences
- Depth in Java
How to prepare
- Answer aloud and timed: Describe your experience with database management systems like MySQL.
- Answer aloud and timed: How would you approach debugging a piece of code?
Behavioral Interviews
reportedBehavioral interviews gauge candidates' fit within the company's culture and values.
What to demonstrate
- Behavioral interviews gauge candidates' fit within the company's culture and values
- Depth in Java
How to prepare
- Prepare three examples from your own work, each with a decision you made and an outcome you can quantify.
- Re-read the description of the behavioral interviews above and write down what you would ask to confirm before it.
PracHub editorial advice for the preparation topics above.
Research the Company
Understanding Dollar General's mission, values, and recent initiatives can help you articulate why you want to work there.
Prepare for Behavioral Questions
Use the STAR method (Situation, Task, Action, Result) to structure your responses to behavioral questions.
Showcase Your Projects
Be ready to discuss past projects in detail, emphasizing your contributions, challenges faced, and the outcomes.
Ask Insightful Questions
Prepare thoughtful questions about the team, projects, and company culture to demonstrate your interest and engagement.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
Write a function that reverses a string.
Write a function that reverses a string.
Approach
- Restate the input: its shape, its size, and what is guaranteed about it.
- Name the brute-force solution and its complexity before improving on it.
- Choose the data structure from the access pattern, not from familiarity.
- State the target complexity and say which constraint rules the naive version out.
Follow-up
- How does this change if the input no longer fits in memory?
- What is the worst case, and how likely is it on real data?
Given a list of integers, find the maximum product of any two integers in the list.
Given a list of integers, find the maximum product of any two integers in the list.
Approach
- Restate the input: its shape, its size, and what is guaranteed about it.
- Name the brute-force solution and its complexity before improving on it.
- Choose the data structure from the access pattern, not from familiarity.
- State the target complexity and say which constraint rules the naive version out.
Follow-up
- How does this change if the input no longer fits in memory?
- What is the worst case, and how likely is it on real data?
Merge partitioned event streams into one ordered feed with bounded lateness
The read-model service consumes 64 log partitions carrying about 4,000 events per second in total. Each partition is ordered within itself, but partitions drift by up to 30 seconds, and the activity feed must present a tenant's events in occurred_at order. Produce the merge. State its complexity, the buffer it requires in events and in bytes, what happens when one partition is idle, and what you do with an event that arrives after you have already emitted its position. Payloads average 1 KB.
Approach
- Merge with a min-heap over the 64 partition heads keyed on (occurred_at, event_id): O(log P) per event and O(n log P) overall. The tie-break on event_id is what makes the output deterministic when two partitions carry the same millisecond, which matters because the feed is paginated and a non-deterministic order reorders pages under the reader.
- Emitting the heap head is only correct once every partition has produced everything up to that timestamp, so the emit condition is a watermark: the minimum across partitions of the highest occurred_at seen, less the allowed lateness. Events are held until the watermark passes them, which is what turns individually ordered streams into a jointly ordered one.
- Size the buffer from the lateness rather than guessing: 4,000 events per second times 30 seconds is 120,000 buffered events, and at 1 KB each about 120 MB of heap. That number is the real price of the ordering guarantee and belongs in front of whoever asked for it.
- Handle the idle partition explicitly, because it fails the feed rather than corrupting it: a partition with no traffic never advances its own maximum, so the watermark freezes and output stops entirely. Either every partition emits a periodic idle marker carrying the broker's current time, or the watermark falls back to wall clock for a partition silent beyond a threshold.
Follow-up
- The lateness budget is raised to five minutes. What is the new buffer, and what besides memory changes?
- The consumer restarts. Where does it resume from, and what does the feed look like for the first 30 seconds?
Find version gaps and relay lag with window functions
outbox_event holds event_id, aggregate_type, aggregate_id, aggregate_version, event_type, payload, status ('pending','published','dead'), attempts, created_at, published_at. A projection is missing rows and you must decide whether the relay skipped events or the consumer dropped them. Write three queries over the last seven days: one listing every aggregate_id whose published aggregate_version sequence has a hole, one giving per-day counts with a running total, and one returning the newest published event per aggregate. For each, say where the window function is evaluated relative to WHERE and LIMIT. PostgreSQL 16.
Approach
- Gaps: compute lead(aggregate_version) OVER (PARTITION BY aggregate_id ORDER BY aggregate_version) in a subquery, then filter next_version <> aggregate_version + 1 in the outer query. Window functions are evaluated after WHERE, GROUP BY and HAVING and before the outer ORDER BY and LIMIT, so the predicate cannot sit in the same WHERE clause and PostgreSQL 16 has no QUALIFY.
- Say what the seven-day filter does to the answer: it truncates every partition, so the first row per aggregate has no predecessor inside the window and a hole spanning the boundary is invisible. Widen the window, or join to resource.version as the authority for the true maximum.
- Running total: SELECT date_trunc('day', created_at) AS d, count() AS n, sum(count()) OVER (ORDER BY date_trunc('day', created_at) ROWS UNBOUNDED PRECEDING). An aggregate inside a window call is legal because grouping runs before windowing. The grouping key is unique per row here so ROWS and RANGE agree, but write the frame anyway — over ungrouped rows with tied timestamps the default RANGE frame pulls in every peer row and the total jumps.
- Newest per aggregate: DISTINCT ON (aggregate_id) ... ORDER BY aggregate_id, aggregate_version DESC is the cheap PostgreSQL-only form when an index matches that order; row_number() OVER (PARTITION BY aggregate_id ORDER BY aggregate_version DESC) = 1 is the portable form and needs a subquery for the same evaluation-order reason as the gap query.
Follow-up
- Relay failover redelivers events. Does a duplicate break the gap query, and how would you detect one from this table alone?
- Turn the gap check into a continuous monitor rather than a query someone runs after an incident. What does it watch?
Stop tag and share joins from fanning out a page
resource_tag is (resource_id, tag_id) with PK (resource_id, tag_id); resource_share is (resource_id, shared_with_user_id, permission). The tagged-and-shared listing inner-joins resource to both, filters tenant_id, tag_id = ANY($2) and shared_with_user_id = $3, orders by updated_at DESC and takes 50. Pages come back with fewer than 50 distinct resources and the total in the header is far too high. Explain the row multiplication, rewrite both the page query and the count query so each is correct, and name the index each one needs. PostgreSQL 16.
Approach
- Do the arithmetic against the predicates that are actually there. An inner join emits one row per matching child row, and both joins are filtered: tag_id = ANY($2) admits only the requested tags, shared_with_user_id = $3 admits one user's share rows. So a resource holding three of the requested tags and shared with $3 once yields three rows, not one — the multiplier is its count of matching tags times its share rows for that single user, and that second factor is 1 unless the table admits duplicate (resource_id, shared_with_user_id) pairs. LIMIT 50 then limits rows rather than resources, and COUNT(*) counts pairs — the header is the product, not the population.
- Reject DISTINCT as the fix. It deduplicates after the product has been built, so the planner must materialise and sort the fanned-out set before the LIMIT can apply, and it leaves any SUM or AVG in the same select list wrong.
- Rewrite both filters as semi-joins, keeping resource as the only row source: AND EXISTS (SELECT 1 FROM resource_tag rt WHERE rt.resource_id = r.resource_id AND rt.tag_id = ANY($2)) and the same shape against resource_share. A semi-join stops at the first match per resource and preserves the driving index order, so ORDER BY updated_at DESC, resource_id DESC LIMIT 50 still stops after 50 rows.
- Count with the same predicates and no join at all: SELECT count(*) FROM resource r WHERE r.tenant_id = $1 AND r.status = 'active' AND EXISTS (...) AND EXISTS (...). Nothing multiplies a resource, so the number is the population.
Follow-up
- The filter changes from 'any of these tags' to 'all of these tags'. Rewrite it and state what it costs relative to the ANY form.
- A resource can be shared with the same user twice under different permissions. Does your count change, and should it?
What experience do you have with Java and its frameworks?
What experience do you have with Java and its frameworks?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
Can you explain the difference between a List and a Set in Java?
Can you explain the difference between a List and a Set in Java?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
Can you discuss a project where you implemented a software solution to solve a business problem?
Can you discuss a project where you implemented a software solution to solve a business problem?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
How would you design an API for a retail inventory system?
How would you design an API for a retail inventory system?
Approach
- Fix the scope first: who calls this, how often, and what they do when it fails.
- Name the read and write paths separately; they rarely have the same bottleneck.
- Choose a partition key and say what query it makes expensive.
- State the consistency you need, and where you are willing to be stale.
Follow-up
- What breaks first when traffic grows ten times?
- How does this behave when that dependency is down for an hour?
What factors do you consider when designing a system for high availability?
What factors do you consider when designing a system for high availability?
Approach
- Fix the scope first: who calls this, how often, and what they do when it fails.
- Name the read and write paths separately; they rarely have the same bottleneck.
- Choose a partition key and say what query it makes expensive.
- State the consistency you need, and where you are willing to be stale.
Follow-up
- What breaks first when traffic grows ten times?
- How does this behave when that dependency is down for an hour?
Describe how you would approach the architecture of a microservices-based application.
Describe how you would approach the architecture of a microservices-based application.
Approach
- Fix the scope first: who calls this, how often, and what they do when it fails.
- Name the read and write paths separately; they rarely have the same bottleneck.
- Choose a partition key and say what query it makes expensive.
- State the consistency you need, and where you are willing to be stale.
Follow-up
- What breaks first when traffic grows ten times?
- How does this behave when that dependency is down for an hour?
Given a set of requirements, how would you approach developing a new feature?
Given a set of requirements, how would you approach developing a new feature?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
How would you approach debugging a piece of code?
How would you approach debugging a piece of code?
Approach
- Establish what changed and when, before forming any theory.
- Pick a bisection that eliminates candidates whichever way it turns out.
- Check the instrumentation before believing the symptom.
- Separate the trigger from the cause; the deploy is rarely the bug.
Follow-up
- What would you look at first, and what would it rule out?
- How would you tell a cause from a coincidence here?
Built from the rounds and topics Dollar General candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the Dollar General loop
- Write out the reported sequence: Initial Screening, Technical Interviews, Behavioral Interviews.
- For each round, write one sentence on what it is judging, from the description above, and mark the one you are least ready for.
Deliverable: A one-page map of the 3 reported rounds, with the weakest marked.
02Work Java
- Spend the session on Java, which Dollar General candidates report being tested on.
- Write one worked example in Java and time yourself on it.
Deliverable: One timed worked example in Java.
03Work Spring Framework
- Spend the session on Spring Framework, which Dollar General candidates report being tested on.
- Write one worked example in Spring Framework and time yourself on it.
Deliverable: One timed worked example in Spring Framework.
04Work Spring Boot
- Spend the session on Spring Boot, which Dollar General candidates report being tested on.
- Write one worked example in Spring Boot and time yourself on it.
Deliverable: One timed worked example in Spring Boot.
05Answer out loud: Technical / Domain Questions
- Answer aloud, timed: What experience do you have with Java and its frameworks?
- Answer aloud, timed: Can you explain the difference between a List and a Set in Java?
Deliverable: Spoken answers to 2 reported Technical / Domain Questions question(s), under time.
06Answer out loud: System Design / Architecture
- Answer aloud, timed: How would you design an API for a retail inventory system?
- Answer aloud, timed: What factors do you consider when designing a system for high availability?
Deliverable: Spoken answers to 2 reported System Design / Architecture question(s), under time.
07Answer out loud: Behavioral / Leadership
- Answer aloud, timed: Describe a time when you faced a significant challenge in a project. How did you handle it?
- Answer aloud, timed: How do you prioritize tasks when working on multiple projects?
Deliverable: Spoken answers to 2 reported Behavioral / Leadership question(s), under time.
Expand any day for tasks and deliverables. Your progress is saved on this device.
Behavioural rounds judge the decision you made and what it cost.
Describe your experience with database management systems like MySQL.
Describe your experience with database management systems like MySQL.
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
Describe a time when you faced a significant challenge in a project. How did you handle it?
Describe a time when you faced a significant challenge in a project. How did you handle it?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
How do you prioritize tasks when working on multiple projects?
How do you prioritize tasks when working on multiple projects?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
What role do you typically take on in team projects?
What role do you typically take on in team projects?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
How would you handle a situation where you disagree with a teammate on a technical solution?
How would you handle a situation where you disagree with a teammate on a technical solution?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
- 01
Describe your experience with database management systems like MySQL.
- 02
Describe a time when you faced a significant challenge in a project. How did you handle it?
- 03
How do you prioritize tasks when working on multiple projects?
- 04
What role do you typically take on in team projects?
How difficult is the interview process?
The interview process is generally considered average in difficulty. Candidates should prepare for both technical and behavioral questions that assess their fit for the role.
Dollar General Software Engineer candidate reports ↗What differentiates successful candidates?
Successful candidates demonstrate strong technical skills, effective problem-solving abilities, and the capacity to collaborate well with others. They also align with Dollar General's values of teamwork and customer focus.
Dollar General Software Engineer candidate reports ↗What is the company culture like at Dollar General?
Dollar General fosters a collaborative and inclusive culture, emphasizing accountability and commitment to serving customers. Employees are encouraged to share ideas and contribute to team success.
Dollar General Software Engineer candidate reports ↗How long does the interview process typically take?
The timeline can vary, but candidates can expect the process to take a few weeks from the initial screening to the final offer.
Dollar General Software Engineer candidate reports ↗Are there remote work opportunities for this role?
While specific remote work policies may vary, candidates should inquire about flexibility during the interview process, especially if location-specific arrangements are critical.
Dollar General Software Engineer candidate reports ↗What topics does Dollar General test in interviews?
Dollar General interviews most often cover Stakeholder Management, Problem Solving, Data Analysis, Behavioral Interviewing, and Analytical Thinking. The exact emphasis depends on the specific role you apply for.
Dollar General Software Engineer candidate reports ↗Sources & methodology 3 sources ↗
No official company page is cited. Rounds and questions come from candidate reports and PracHub editorial material; each source shows the date it was read.
- 01Dollar General Software Engineer candidate reports ↗
Company-reported rounds, questions and FAQ.
Candidate reports · Accessed 2026-09-22 - 02PracHub Software Engineer practice ↗
PracHub practice material, not company-reported.
PracHub page · Accessed 2026-09-22 - 03PracHub preparation framework ↗
PracHub preparation guidance.
PracHub page · Accessed 2026-09-22
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