Accenture Java Full Stack with React Interview Questions & Answers
Curated interview practice questions with answers. These are practice scenarios, not a verified list of past interview questions.
About Accenture hiring for Java Full Stack with React roles
Accenture is a global professional services company offering strategy, consulting, technology, operations and digital services. India hosts a large share of its workforce, delivering software engineering, testing, cloud, data and AI projects for clients worldwide. It hires freshers and experienced professionals in India for associate software engineer, test engineer, data analyst and analytics consultant roles.
For Java Full Stack with React roles, this Accenture practice set focuses most on Collections and Streams (7), Core Java (5), React Frontend (4), REST APIs, Security and Microservices (4). It has 8 easy, 18 medium, 4 hard questions, so you can start easy and work up to the harder ones.
Company type
Consulting
Headquarters
Dublin, Ireland
Main India offices
Bengaluru, Hyderabad, Pune, Mumbai, Gurugram
Accenture Java Full Stack with React interview process
Online assessment (cognitive + technical MCQs)
Coding assessment
Communication assessment
Technical and HR interview
Typical pattern based on public candidate experiences. Rounds vary by role, team and year.
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useEffect runs after the component renders. With no dependency array it runs after every render, with an empty array it runs once after mount, and with values like [userId] it runs again whenever those values change. Return a cleanup function to cancel subscriptions, timers or requests before the next run or on unmount. Missing dependencies cause stale data, so follow the exhaustive-deps lint rule. Effects are for syncing with external systems, not for computing derived values.
02
Write a query that shows daily sales with a running total for the month.
SELECT order_date,
SUM(amount) AS daily_sales,
SUM(SUM(amount)) OVER (
ORDER BY order_date
ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
) AS running_total
FROM orders
WHERE order_date >= DATE '2026-10-01'
AND order_date < DATE '2026-11-01'
GROUP BY order_date
ORDER BY order_date;
03
How do code splitting and lazy loading work in React?
Code splitting breaks the JavaScript bundle into smaller chunks loaded on demand, which improves first load time. React.lazy with a dynamic import, such as const Reports = lazy(() => import('./Reports')), loads the component only when it renders, and Suspense shows a fallback while it loads. Splitting by route is the most common pattern. Bundlers like Vite create the chunks automatically from dynamic imports.
04
Implement pagination and sorting for a product list API.
CORS is a browser rule that blocks JavaScript from calling a different origin unless the server allows it with response headers like Access-Control-Allow-Origin. A React app on localhost:5173 calling an API on localhost:8080 is cross-origin. In Spring, define a CorsConfigurationSource bean with the allowed origins, methods and headers, and enable http.cors() in the security chain so preflight OPTIONS requests pass. Never use a wildcard origin together with credentials.
06
What triggers a re-render in React, and how does reconciliation decide what to update?
A component re-renders when its state changes, its parent re-renders, or a context it uses changes. Props changing is not itself the trigger; parent re-render is. During reconciliation React compares element types: a different type at the same position destroys and recreates the subtree, while the same type updates props. Keys identify list children. React.memo skips a child re-render when its props are shallowly equal.
07
What are the correct and incorrect ways to use Optional?
Use Optional as a return type when a value may be absent, and consume it with map, filter, orElse, orElseGet or orElseThrow. Avoid calling get() without checking, avoid Optional fields in entities or DTOs, avoid Optional parameters and never return null from a method that returns Optional. Prefer orElseGet over orElse when the default is expensive, because orElse always evaluates its argument.
08
What changed when moving from Spring Boot 2 to Spring Boot 3?
Spring Boot 3 requires Java 17 or later and is built on Spring Framework 6. The biggest migration task is the switch from javax.* to jakarta.* packages for persistence, validation and servlet APIs. Spring Security 6 removed WebSecurityConfigurerAdapter in favour of SecurityFilterChain beans. Boot 3 also supports GraalVM native images, Micrometer observation and tracing, and from 3.2 the RestClient and virtual thread support.
09
Your code has frequent NullPointerExceptions from repository lookups. How would you redesign it?
Return Optional from lookup methods so callers must handle the missing case, for example findById(id).orElseThrow(). Validate inputs at the API boundary with Bean Validation, initialise collections to empty lists instead of null and use Objects.requireNonNull in constructors. Java 17 helpful NPE messages show which variable was null, which speeds debugging. Do not use Optional for fields or method parameters; it is meant for return values.
10
Find the second highest salary from a list of employees using streams.
Pure JWTs cannot be revoked, so keep access tokens short-lived, around 10 to 15 minutes, and use refresh tokens stored server-side and rotated on each use. On logout or theft, revoke the refresh token. For immediate blocking, keep a denylist of token IDs or a per-user token version in Redis and check it in the filter. Send refresh tokens in HttpOnly, Secure, SameSite cookies to reduce theft through XSS.
13
You need to store unique usernames and always display them in alphabetical order. Which collection do you pick?
A TreeSet fits because it rejects duplicates and keeps elements sorted using natural order or a Comparator, with O(log n) add and lookup. Use String.CASE_INSENSITIVE_ORDER as the comparator if Rahul and rahul should be treated as the same. If you only need sorting once at display time, a HashSet followed by sorting may be faster. For concurrent access, ConcurrentSkipListSet is the thread-safe sorted alternative.
14
A security test shows a stored XSS vulnerability in a comments feature. How do you fix it?
Stored XSS happens when user input containing script is saved and later rendered as HTML. React escapes text by default, so look for dangerouslySetInnerHTML, direct innerHTML or unsafe URL attributes like javascript: links. If rich text is required, sanitise it with a library like DOMPurify, and validate on the server too. Add a Content Security Policy header and keep tokens out of JavaScript-readable storage to limit damage.
15
What are the options for spring.jpa.hibernate.ddl-auto and which should be used in production?
none does nothing, validate checks that the schema matches entities, update alters tables to add missing columns, create drops and recreates the schema at startup and create-drop also drops it at shutdown. update and create are fine for learning but risky in production because they cannot handle renames or data migrations safely. In production use validate or none, and manage schema changes with Flyway or Liquibase scripts.
16
A security review found a login query built by string concatenation. What is the risk and the fix?
Concatenating user input into SQL allows SQL injection, where input like ' OR '1'='1 changes the query and can bypass login or dump data. Use parameterised queries: PreparedStatement with ? placeholders, Spring Data method queries, or @Query with named parameters, which send values separately from the SQL. Also validate input, use a database user with least privilege and never show raw SQL errors to users.
17
You are passing the same user prop through five levels of components. What would you do?
This is prop drilling, which makes intermediate components depend on data they do not use. For global, rarely changing data like the logged-in user or theme, create a context with a provider at the top and read it with useContext through a custom hook such as useAuth. Alternatively, use component composition, passing ready-made elements as children. For complex shared state, a store like Zustand or Redux Toolkit is suitable.
18
How does the this keyword work, and how do arrow functions change it?
In a regular function, this depends on how the function is called: the object before the dot in a method call, undefined in strict mode for a plain call, the new object with new, or a value set by call, apply or bind. Arrow functions do not have their own this; they use this from the surrounding scope. That makes arrows ideal for callbacks inside methods, but unsuitable as object methods that need their own this.
Fail-fast iterators, used by ArrayList and HashMap, track a modification count and throw ConcurrentModificationException if the collection is structurally changed during iteration, except through the iterator's own remove. Fail-safe or weakly consistent iterators, used by CopyOnWriteArrayList and ConcurrentHashMap, work on a snapshot or tolerate concurrent changes and never throw that exception, but they may not show the latest updates.
20
What is the difference between JPA, Hibernate and Spring Data JPA?
JPA, now Jakarta Persistence, is a specification that defines annotations and the EntityManager API for object-relational mapping. Hibernate is the most widely used implementation of that specification and adds extra features. Spring Data JPA is a layer above JPA that generates repository implementations from interfaces, so methods like findByEmail are created automatically. In a Spring Boot app you write against Spring Data, which uses JPA, which is implemented by Hibernate.
The GC frees objects that are no longer reachable from GC roots such as thread stacks and static fields. Most objects die young, so the heap is generational: minor collections clean the young generation often and survivors are promoted. G1 is the default collector since Java 9 and targets predictable pause times by collecting regions. ZGC and Shenandoah offer sub-millisecond pauses for large heaps. Tuning usually starts with -Xmx and choosing the collector, not dozens of flags.
22
You need a thread-safe singleton for a configuration loader. How do you implement it?
The simplest safe options are an enum singleton or the holder idiom. With the holder idiom, a private static nested class holds the instance, and the JVM's class loading guarantees lazy, thread-safe initialisation without synchronization. Double-checked locking also works but needs a volatile field. In a Spring application you usually do not write singletons at all, because beans are singleton-scoped by default and the container manages them.
23
Using streams, group employees by department and count them.
Map<String, Long> countByDept = employees.stream()
.collect(Collectors.groupingBy(
Employee::getDepartment,
Collectors.counting()));
// Average salary per department:
Map<String, Double> avgSalary = employees.stream()
.collect(Collectors.groupingBy(
Employee::getDepartment,
Collectors.averagingDouble(Employee::getSalary)));
// Use TreeMap::new as the second argument to get sorted keys.
REST treats everything as a resource identified by a URL, such as /api/orders/42, and uses standard HTTP methods to act on it. Requests are stateless, so each one carries all the information needed, including the auth token. Responses use proper status codes and representations, usually JSON, and can be cacheable. Good REST design uses nouns in URLs, plural resource names, nested paths for relations and query parameters for filtering and pagination.
25
Write a production-friendly Dockerfile for a Spring Boot application.
final is a keyword: a final variable cannot be reassigned, a final method cannot be overridden and a final class cannot be extended. finally is a block after try or catch that always runs, used for cleanup, although try-with-resources is now preferred. finalize() was an Object method called before garbage collection; it is deprecated for removal because its timing is unpredictable. Use Cleaner or try-with-resources instead.
29
Your React app gets 403 Forbidden on POST requests to Spring Boot, but GET works. What is the likely cause?
With Spring Security enabled, CSRF protection is on by default and blocks POST, PUT and DELETE that lack a CSRF token, while GET is allowed. For a stateless JWT API, disable CSRF in the SecurityFilterChain. If you use session cookies, keep CSRF and send the token with CookieCsrfTokenRepository. Also check CORS, because a rejected preflight OPTIONS request or a missing role in authorization rules can produce the same symptom.
30
What are intermediate and terminal operations in Java Streams?
Intermediate operations such as filter, map, sorted and distinct return a new stream and are lazy; nothing runs until a terminal operation is called. Terminal operations such as collect, forEach, count, reduce and findFirst trigger processing and produce a result. Laziness allows short-circuiting: with findFirst, elements are processed one by one only until a match is found. A stream can be consumed only once.
Tips to crack the Accenture Java Full Stack with React interview
Practise the communication assessment, which checks spoken English through reading, listening and repeating sentences in a recorded format.
Revise MS Office, cloud basics, networking and pseudocode, as Accenture technical MCQs often cover these general IT topics.
Read about Accenture's focus on cloud, data and AI and be ready to discuss how you would work in client-facing teams.
Keep a one-minute story ready for every project on your CV: problem, your part, tools, result.
Practise the hard questions on this page aloud; Accenture interviewers usually ask follow-ups on your first answer.
Frequently asked questions
How many rounds are there in the Accenture Java Full Stack with React interview?
Candidates usually go through 4 stages: Online assessment (cognitive + technical MCQs); Coding assessment; Communication assessment; Technical and HR interview. The exact rounds change with the role, team, location and your experience, so confirm the process with the recruiter.
Which topics should I prepare for the Accenture Java Full Stack with React interview?
This practice set leans on Collections and Streams (7), Core Java (5), React Frontend (4), REST APIs, Security and Microservices (4). Revise those first, then practise explaining one or two of your own projects end to end, because most Accenture interviewers ask you to walk through real work.
Are these the exact questions asked at Accenture?
No. These are curated practice questions that match the skills and difficulty usually tested in consulting interviews like Accenture's. They are not a leaked or verified list of past questions.
Where does Accenture hire Java Full Stack with React professionals in India?
Accenture has large teams in Bengaluru, Hyderabad, Pune, Mumbai, Gurugram. Openings and locations change often, so check the Accenture careers page and filter by city and experience.
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