Java Spring Boot Interview Questions for India 2026

Fundamentals tested at every level: OOP principles: Abstraction (hiding implementation via interfaces), Encapsulation (private fields + public methods), Inheritance (extends), Polymorphism (method overriding at runtime). Collections framework: HashMap internals (hashCode, equals, load factor, rehashing), ArrayList vs LinkedList, ConcurrentHashMap vs synchronized HashMap. Generics and type erasure. Exception hierarchy: Checked (IOException, SQLException: must handle) vs Unchecked (RuntimeException: optional). Java 8+ features: Streams, lambda expressions, Optional, functional interfaces (Predicate, Function, Consumer, Supplier), CompletableFuture. String immutability and String pool. equals() vs == distinction.

Spring Boot interview questions cover both configuration and concepts. Key annotations: @SpringBootApplication (combines @Configuration, @EnableAutoConfiguration, @ComponentScan), @RestController, @Service, @Repository, @Component, @Autowired, @Bean, @Configuration. Auto-configuration: Spring Boot auto-configures based on classpath: @ConditionalOnClass, @ConditionalOnProperty mechanisms. Dependency Injection: Constructor injection (preferred for required dependencies) vs field injection via @Autowired (not recommended). Application properties: application.properties vs application.yml, profile-specific configs (application-dev.yml). Actuator: /actuator/health, /actuator/metrics, /actuator/info: production monitoring endpoints.

REST API design with Spring MVC: @GetMapping, @PostMapping, @PutMapping, @DeleteMapping, @PathVariable, @RequestParam, @RequestBody. ResponseEntity for controlling status codes. Exception handling: @ControllerAdvice + @ExceptionHandler for global exception handling. JPA and Hibernate: Entity mapping (@Entity, @Table, @Id, @GeneratedValue, @Column). Relationships: @OneToMany (lazy loading by default), @ManyToOne, @ManyToMany. FetchType: LAZY (load on access) vs EAGER (load immediately): the N+1 problem and how JOIN FETCH or @EntityGraph solve it. JPQL vs native queries. Transaction management: @Transactional, propagation levels, rollback rules.

Multithreading: Thread creation (extending Thread vs implementing Runnable vs Callable + Future). Executor framework: ThreadPoolExecutor, Executors.newFixedThreadPool(). Synchronization: synchronized blocks, ReentrantLock, volatile keyword. ConcurrentHashMap vs HashMap in multithreaded contexts. Common problems: deadlock, livelock, race conditions. Microservices with Spring Boot: Service discovery with Eureka or Consul. API gateway: Spring Cloud Gateway. Circuit breaker: Resilience4j (@CircuitBreaker annotation). Feign client for declarative REST calls. Distributed tracing with Zipkin. Config server: centralised configuration with Spring Cloud Config. These Spring Cloud topics appear at senior and architect levels.

Java Spring Boot developers command strong salaries across Indian IT hubs in 2026. Freshers at service firms like Infosys, Wipro, and TCS typically start at 4 to 6 LPA, while product companies such as Flipkart, PhonePe, and Swiggy offer 12 to 18 LPA for two to three years of experience. Senior engineers with microservices and cloud experience earn 25 to 40 LPA at MNCs like Goldman Sachs Bengaluru or JP Morgan Hyderabad. FAANG-equivalent roles at Amazon India or Google Hyderabad can reach 60 to 90 LPA including RSUs, making Java one of the highest-paying backend stacks in the country.

Infosys and Wipro run a three-stage process: an online InfyTQ or NLTH platform test, a technical interview covering collections and JDBC, and an HR round. Product companies like Meesho and Razorpay prefer live coding on HackerRank followed by a system design discussion. Paytm's backend team frequently asks about database connection pooling with HikariCP and circuit breaker patterns using Resilience4j. Zepto and Blinkit focus on low-latency API design given their quick-commerce constraints. Expect questions on Spring Security JWT filters and Kafka consumer groups at fintech firms including CRED and BharatPe, reflecting their real-time transaction architectures.

Interviewers at Indian product companies consistently ask candidates to explain the difference between @Component, @Service, and @Repository, and why the distinction matters beyond semantics. Spring Boot auto-configuration internals, specifically how @SpringBootApplication triggers component scanning and how to override a default bean, appear frequently at mid-level interviews. Questions on transactional propagation levels such as REQUIRED versus REQUIRES_NEW are common at banking and fintech firms where transaction integrity is critical. Candidates are also expected to demonstrate proficiency with Spring Actuator endpoints for health checks, a near-universal requirement in cloud-deployed microservices running on AWS or Azure in Indian engineering teams.