Interview guides · Sra Group

Sra Group Software Engineer Interview Guide

Sra Group Software Engineer interview guide: reported rounds, questions and how candidates describe the process.

The 60-second brief

A Software Engineer at Sra Group plays a vital role in designing, developing, and maintaining complex technology solutions that support critical government, defense, and civil agency missions. Because Sra Group operates primarily as a federal systems integrator and defense contractor, software engineering here goes far beyond writing isolated code. You will build highly secure, resilient, and scalable systems that directly impact national security, public infrastructure, and large-scale federal operations. The work is highly interdisciplinary, often bridging the gap between pure software development, network engineering, and systems integration. Engineers are tasked with solving complex problems in secure environments, ranging from high-throughput network routing and communication protocols to specialized embedded systems and enterprise Java applications.

This guide is scoped to a Software Engineer candidate at Sra Group.

Focus areas

Networking troubleshooting (OSI Layer 1 to Layer 4)
Technical phone screening
SIP (Session Initiation Protocol)

The Sra Group interview process

Sra Group candidates report 3 rounds over 3-5 weeks. The stages below are what candidates describe, not a published process.

Initial Screening

A corporate recruiter reviews your resume, salary expectations, and basic qualifications.

What to demonstrate

A corporate recruiter reviews your resume, salary expectations, and basic qualifications
Depth in Networking troubleshooting (OSI Layer 1 to Layer 4)

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 Phone Interview

A phone interview with a project manager, lead engineer, or technical director focusing on core engineering skills and past project experience.

What to demonstrate

A phone interview with a project manager, lead engineer, or technical director focusing on core engineering skills and past project experience
Depth in Networking troubleshooting (OSI Layer 1 to Layer 4)

How to prepare

Answer aloud and timed: What is Media Gateway Control Protocol (MGCP), and how would you approach debugging a failed call flow using MGCP debug logs?
Answer aloud and timed: How do you optimize socket-level communications in a high-latency, secure network environment?

Panel Interview

A comprehensive interview that may be virtual or in-person, involving deep-dive technical questions and behavioral evaluations with multiple team members.

What to demonstrate

A comprehensive interview that may be virtual or in-person, involving deep-dive technical questions and behavioral evaluations with multiple team members
Depth in Networking troubleshooting (OSI Layer 1 to Layer 4)

How to prepare

Answer aloud and timed: How would you implement dependency injection in a multi-tier Java enterprise application, and what are the architectural benefits?
Answer aloud and timed: Describe a scenario where you had to refactor a legacy codebase. What steps did you take to ensure system stability during the transition?

Where candidates lose points

Understand the Government Contracting Dynamic

Working at Sra Group means your ultimate customer is often a government agency. Be prepared to discuss how you manage client relationships, handle shifting government requirements, and maintain professionalism when representing the company on-site.

Highlight Your Troubleshooting Methodology

When answering technical questions, do not just give the final answer. Explain your process for diagnosing problems, isolating variables, and validating solutions. Showing a structured, disciplined analytical mindset is highly valued by technical leads.

Be Proactive and Patient

The hiring and onboarding process in federal contracting can sometimes be slow due to background checks and contract approvals. Maintain a positive, proactive attitude, keep in touch with your hiring manager, and use the waiting periods to build a strong rapport with the team.

Questions & practice

Explain how you manage thread safety and concurrency in high-throughput backend applications.

Medium · Software Development & Systems Integrati

Approach

Say what the runtime actually does before reasoning about the code.
Name what is shared across threads and what owns each piece of state.
Identify the window where an invariant is briefly untrue.
Distinguish a value from a reference to it, and say which one you handed out.

Follow-up

What happens if two callers reach this at the same time?
Where could this allocate more than you expect?

Find overlapping job attempts and peak concurrency from lease records

Medium · sweep line · intervals · leases

A day of job_run history yields about 50,000,000 attempt records: (job_run_id, job_type, attempt, started_at, finished_at which is NULL when the worker died, lease_expires_at). Leases expire on a clock, so a job that outran its lease ran twice. Produce (a) every job_run_id whose attempts overlapped in wall-clock time and (b) the peak number of simultaneously running attempts per job_type with the minute it occurred. Target O(n log n). State how you treat a NULL finished_at and what clock skew does to your answer.

Approach

Define the interval before sorting anything: an attempt occupies [started_at, COALESCE(finished_at, lease_expires_at)). finished_at is observed and lease_expires_at is only a promise, so every attempt without a finish contributes an estimate and the whole result is a lower bound on overlap rather than an exact count.
For peak concurrency, sweep: emit 2n endpoints, sort by (timestamp, kind) with ends ordered before starts at equal timestamps, then walk the sequence maintaining a counter per job_type and record each type's maximum with its timestamp. O(n log n) dominated by the sort, O(n) space, or O(1) extra if the sort is external and the walk streams.
For overlap detection, do not compare attempts pairwise. A single global sort by (job_run_id, started_at) gives both the grouping and the order; within a group, keep the maximum end seen so far and report an overlap exactly when the next start is less than that running maximum, which is one linear pass after the sort.
Half-open intervals matter and are easy to get wrong: with closed intervals an attempt ending at the same millisecond another begins reads as concurrency two, and across 50,000,000 records that artefact swamps the real signal.

Follow-up

A handler is not idempotent and you have found 400 overlapping jobs. Which of them actually caused damage, and what would you query to find out?
Peak concurrency for one job_type is 4 against a configured cap of 4. Is the cap working, or is the data hiding attempts that never started?

Archive a resource graph without breaking live references or recursing

Medium · graph traversal · topological order · tenant isolation

Resources reference other resources within a tenant; for the largest tenant the reference table holds up to 2,000,000 nodes and 8,000,000 edges. Archiving a resource must archive everything reachable from it that nothing outside the set still references, refuse when a live external referrer exists, and terminate when references form cycles, which they legitimately do. Produce the archive order and the refusal list, targeting O(V+E). Say what stops the traversal crossing a tenant boundary, and why recursion is the wrong control structure at this size.

Approach

Load the subgraph with the tenant predicate on both endpoints of the edge, not only on the side you started from. Scoping the left table alone is the classic cross-tenant leak: one mis-entered edge then pulls another tenant's resources into the traversal and, worse, into the archive.
Traverse iteratively with an explicit stack. A 2,000,000-node graph can hold a chain deep enough to exhaust a native stack in the low tens of thousands of frames, and that failure is a process crash rather than an error you can return.
Treat cycles as data rather than corruption: compute strongly connected components with Tarjan in O(V+E) using its own explicit stack, then condense. The condensation is a DAG, so a topological order over it gives the archive order, and every member of a component archives in one transaction because no order within a cycle is valid.
Decide refusals with reverse edges. A candidate is archivable only if every in-edge originates inside the candidate set, so build the transpose or count in-degrees restricted to the visited set, and emit each blocked resource with the id of the external referrer, which is the only part of the answer an operator can act on.

Follow-up

The graph is read in one query and the archive writes a minute later. What can change in between, and how do you make the write safe?
The candidate set is 400,000 resources. Is that one transaction, and if not, what does a half-finished archive look like to a reader?

Keep soft-deleted accounts from blocking re-registration

Easy · soft delete · unique constraints · engine differences

app_user holds user_id, tenant_id, email CITEXT, password_hash (NULL for SSO principals), email_verified_at, auth_version, status ('invited','active','suspended','deactivated'), created_at, updated_at, deleted_at. Two live accounts for one address inside a tenant must be impossible, but an address freed by a soft delete must be reusable, and the same tenant may delete and re-register it repeatedly. Write the uniqueness DDL for PostgreSQL 16, then the equivalent for MySQL 8 where partial indexes do not exist, and say what each permits once three deleted rows already hold that address.

Approach

Start from what is actually unique: not (tenant_id, email), but (tenant_id, email) among live rows. PostgreSQL says that directly — CREATE UNIQUE INDEX app_user_live_email ON app_user (tenant_id, email) WHERE deleted_at IS NULL. A full constraint over the same two columns burns the address permanently the first time someone deletes an account.
Keep case-insensitivity in the type or the index, never in the application: CITEXT as given, or UNIQUE (tenant_id, lower(email)) as an expression index where the extension is unavailable. A case-sensitive unique column is exactly how two accounts for one human appear.
For MySQL 8 the predicate has to move inside the key: add a discriminator column that is a constant 0 while the row is live and is set to user_id on delete, with UNIQUE (tenant_id, email, deleted_marker). Live rows share the constant and still collide; deleted rows differ from each other and stop colliding.
State the NULL variant and its dependency: leaving the marker NULL for deleted rows also works, because a unique index treats NULLs as distinct — true in MySQL, and true in PostgreSQL only under the default NULLS DISTINCT, which PostgreSQL 15 lets you reverse. Check the polarity against the three existing deleted rows: constant-on-live is what preserves the collision you want, and reversing it silently admits duplicate live accounts.

Follow-up

A deleted account re-registers with the same address the next day. Do the old resource rows follow the new user_id, and how does the API keep the two principals apart?
How do you honour an erasure request while resource_revision.actor_user_id still references this table?

Find version gaps and relay lag with window functions

Medium · window functions · event tables · frame semantics

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?

How do SIP and H.323 protocols differ in managing real-time multimedia sessions?

Medium · Network & Protocol Engineering

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 do you optimize socket-level communications in a high-latency, secure network environment?

Medium · Network & Protocol Engineering

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 implement dependency injection in a multi-tier Java enterprise application, and what are the arc

Medium · Software Development & Systems Integrati

How would you implement dependency injection in a multi-tier Java enterprise application, and what are the architectural benefits?

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 a scenario where you had to refactor a legacy codebase. What steps did you take to ensure system stab

Medium · Software Development & Systems Integrati

Describe a scenario where you had to refactor a legacy codebase. What steps did you take to ensure system stability during the transition?

Approach

Say who the caller is and what they do when the call fails halfway.
Define the identity of a request so a retry cannot double-apply it.
Separate accepted, pending, failed and confirmed; they are different facts.
Design the error taxonomy before the success shape; callers branch on it.

Follow-up

What happens if the caller retries after a timeout?
How does a client discover it is on an old version of this contract?

Walk us through a complex system architecture you designed. How did you handle data persistence and system bou

Medium · Software Development & Systems Integrati

Walk us through a complex system architecture you designed. How did you handle data persistence and system boundaries?

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 your hands-on experience with US Navy P-9290 Certification and how it influences the design and testi

Medium · Specialized Domain & Compliance

Describe your hands-on experience with US Navy P-9290 Certification and how it influences the design and testing of maritime systems.

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?

How do you approach software design and operations for manned submersible vehicles or comparable high-risk har

Medium · Specialized Domain & Compliance

How do you approach software design and operations for manned submersible vehicles or comparable high-risk hardware environments?

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 methodologies do you use to ensure software compliance with strict government and international safety st

Medium · Specialized Domain & Compliance

What methodologies do you use to ensure software compliance with strict government and international safety standards?

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?

Explain the step-by-step process of troubleshooting a network connection failure from Layer 1 (Physical) throu

Medium · Network & Protocol Engineering

Explain the step-by-step process of troubleshooting a network connection failure from Layer 1 (Physical) through Layer 4 (Transport).

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?

What is Media Gateway Control Protocol (MGCP), and how would you approach debugging a failed call flow using M

Medium · Network & Protocol Engineering

What is Media Gateway Control Protocol (MGCP), and how would you approach debugging a failed call flow using MGCP debug logs?

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?

Suggested practice checklist

Built from the rounds and topics Sra Group candidates report.

Day 1 — Map the Sra Group loop

Write out the reported sequence: Initial Screening, Technical Phone Interview, Panel Interview.
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.

Day 2 — Work Networking troubleshooting (OSI Layer 1 to Layer 4)

Spend the session on Networking troubleshooting (OSI Layer 1 to Layer 4), which Sra Group candidates report being tested on.
Write one worked example in Networking troubleshooting (OSI Layer 1 to Layer 4) and time yourself on it.

Deliverable: One timed worked example in Networking troubleshooting (OSI Layer 1 to Layer 4).

Day 3 — Work Technical phone screening

Spend the session on Technical phone screening, which Sra Group candidates report being tested on.
Write one worked example in Technical phone screening and time yourself on it.

Deliverable: One timed worked example in Technical phone screening.

Day 4 — Work SIP (Session Initiation Protocol)

Spend the session on SIP (Session Initiation Protocol), which Sra Group candidates report being tested on.
Write one worked example in SIP (Session Initiation Protocol) and time yourself on it.

Deliverable: One timed worked example in SIP (Session Initiation Protocol).

Day 5 — Answer out loud: Network & Protocol Engineering

Answer aloud, timed: Explain the step-by-step process of troubleshooting a network connection failure from Layer 1 (Physical) through Layer 4 (Transport).
Answer aloud, timed: How do SIP and H.323 protocols differ in managing real-time multimedia sessions?

Deliverable: Spoken answers to 2 reported Network & Protocol Engineering question(s), under time.

Day 6 — Answer out loud: Software Development & Systems Integration

Answer aloud, timed: How would you implement dependency injection in a multi-tier Java enterprise application, and what are the architectural benefits?
Answer aloud, timed: Describe a scenario where you had to refactor a legacy codebase. What steps did you take to ensure system stability during the transition?

Deliverable: Spoken answers to 2 reported Software Development & Systems Integration question(s), under time.

Day 7 — Answer out loud: Specialized Domain & Compliance

Answer aloud, timed: Describe your hands-on experience with US Navy P-9290 Certification and how it influences the design and testing of maritime systems.
Answer aloud, timed: How do you approach software design and operations for manned submersible vehicles or comparable high-risk hardware environments?

Deliverable: Spoken answers to 2 reported Specialized Domain & Compliance question(s), under time.

Behavioural preparation

Behavioural rounds judge the decision you made and what it cost.

Describe a time when a client’s technical requirements were ambiguous or conflicting. How did you clarify thei

Medium · Behavioral & Workplace Scenarios

Describe a time when a client’s technical requirements were ambiguous or conflicting. How did you clarify their needs and deliver the 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?

How do you handle a situation where you are assigned to work at a secure client site with limited access to ex

Medium · Behavioral & Workplace Scenarios

How do you handle a situation where you are assigned to work at a secure client site with limited access to external development resources?

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?

Tell me about a time you had to learn a highly specialized programming language or domain concept quickly to m

Medium · Behavioral & Workplace Scenarios

Tell me about a time you had to learn a highly specialized programming language or domain concept quickly to meet a project deadline.

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 manage communication and alignment when working as part of a multi-vendor project team?

Medium · Behavioral & Workplace Scenarios

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?