Advanced Java Essentials – Episode 22: Spring Boot, REST APIs and Microservices (Updated June 2026) (Updated June 2026)

What most people do not realize about the Java job market in 2026 is that Core Java is just the entry ticket — what employers at TCS, Infosys, Tata Tech, and KPIT actually test for is your command of Spring Boot, REST APIs, and microservices. TCS announced 12,000 layoffs in July 2025 while simultaneously ramping up hiring for Java engineers with Spring Boot expertise — the demand for the right skills has never been sharper. Episode 22 of our Advanced Java series brings the ecosystem together: Spring Framework fundamentals, building production-grade REST APIs with Spring Boot, Spring Data JPA for database work, and an introduction to the microservices patterns that power enterprise applications at scale.

Why Spring Boot Is the Java Framework Every Developer Needs in 2026

Spring Boot is not just popular — it is the de facto standard for Java backend development in Indian enterprise IT. Here is the thing: plain Java EE (Jakarta EE) requires XML configuration files, application server setup, and a significant amount of scaffolding code before you write a single line of business logic. Spring Boot eliminates all of that. Auto-configuration detects your dependencies and sets sensible defaults automatically. Embedded servers (Tomcat, Jetty, Undertow) mean you package your application as a single executable JAR — no separate server deployment needed. Spring Initializr (start.spring.io) generates a ready-to-run project skeleton in 30 seconds. The Spring ecosystem is also enormous — Spring Data, Spring Security, Spring Cloud, Spring Batch — each a production-grade solution for a specific domain problem. Companies like Tata Consultancy Services, Infosys, Wipro, HCL, and virtually every Indian fintech use Spring Boot for their Java applications. The consequence for job seekers: a Java developer without Spring Boot experience has a significantly narrowed job market compared to one who knows it well.

Building Your First REST API with Spring Boot

A REST API (Representational State Transfer Application Programming Interface) is how your Spring Boot application communicates with the outside world — other services, mobile apps, web frontends. Building one in Spring Boot is genuinely straightforward once you understand the core annotations. @RestController marks a class as an API endpoint. @GetMapping, @PostMapping, @PutMapping, and @DeleteMapping map HTTP methods to Java methods. @RequestBody binds incoming JSON to a Java object. @PathVariable and @RequestParam extract URL path segments and query parameters. A minimal REST API that creates, reads, updates, and deletes records (CRUD) can be written in under 50 lines with Spring Boot. The critical details to get right: HTTP status codes (200 for success, 201 for created, 404 for not found, 400 for bad request, 500 for server error), request validation using @Valid and Bean Validation annotations, and consistent error response structure. These details are exactly what senior developers check in code reviews and what interviewers probe for. Practice by building a simple To-Do or Student Records API — commit it to GitHub as portfolio evidence.

Framework/Tech	Use Case	Learning Curve	Job Demand India	Avg Fresher Salary
Spring Boot	REST APIs, Microservices	Medium	Very High	Rs 5–8 LPA
Jakarta EE	Enterprise Java apps	High	Medium	Rs 4–7 LPA
Spring MVC	Web MVC applications	Medium	High	Rs 4.5–7 LPA
Quarkus	Cloud-native Java	Medium	Growing	Rs 6–10 LPA
Micronaut	Microservices, serverless	Medium	Niche	Rs 6–10 LPA

Spring Data JPA: Database Access Without the Boilerplate

Spring Data JPA is the layer that makes database work in Spring Boot practical rather than painful. Without it, every database operation requires writing JDBC connection code, PreparedStatement objects, and ResultSet iteration — repetitive, verbose, and error-prone. Spring Data JPA uses Hibernate under the hood (with JPA as the abstraction layer) and requires you to define only your entity classes and repository interfaces. The magic: extend JpaRepository and Spring generates findById, findAll, save, delete, and pagination methods automatically — no implementation code needed. Custom queries use method name conventions (findByNameAndEmail) or @Query annotations for complex JPQL. The features that matter most in production: @Transactional for atomic operations, pagination with Pageable, and auditing with @CreatedDate and @LastModifiedDate. The N+1 query problem is the most common performance trap — always use @EntityGraph or JOIN FETCH for collections. Master these patterns and your database code will satisfy senior code reviewers at Infosys, Cognizant, and backend-heavy startups in Pune and Hyderabad.

Spring Security: Authentication and Authorization Essentials

Spring Security is the framework for handling authentication (who are you?) and authorization (what are you allowed to do?) in Spring Boot applications. Modern Spring Security (6.x) uses a SecurityFilterChain bean configuration approach that replaces the older WebSecurityConfigurerAdapter — this is a breaking change many tutorials get wrong, so pay attention to version. JWT (JSON Web Token) authentication is the standard for REST APIs: the client authenticates once, receives a signed token, and sends that token on every subsequent request. Spring Security validates the token without hitting the database on each call. OAuth2 integration (with Google, GitHub, or your own authorization server) is the other major pattern for enterprise applications. What interviewers test: the difference between authentication and authorization, how to prevent CSRF attacks, how password hashing works (BCrypt), and why session-based authentication does not work cleanly in stateless microservices. Hands-on practice with a JWT-secured Spring Boot API is essential interview preparation for mid-level and above Java roles.

Introduction to Microservices Architecture with Spring Cloud

Microservices architecture is the pattern that enterprise companies adopt when a single monolithic application becomes too large for one team to manage, deploy, and scale independently. Each microservice is a small, independent application responsible for one business capability — User Service, Order Service, Payment Service — each with its own database and deployable without touching other services. Spring Cloud is the Spring ecosystem's answer to microservices infrastructure concerns: Eureka for service discovery (services find each other by name, not hardcoded IP), Spring Cloud Gateway for API routing and load balancing, Spring Cloud Config for centralized configuration management, and Resilience4j for circuit breaking and fault tolerance. The key insight for beginners: you do not start with microservices. Start with a well-structured Spring Boot monolith, learn it thoroughly, then extract services when clear boundaries emerge. Companies like Tata Tech, KPIT, and mid-size product companies in the Pune tech corridor typically introduce microservices after the initial monolith proves its architecture.

Java Spring Boot Career Guide and Salaries in India 2026

Java with Spring Boot is one of the most employable skill combinations in Indian IT right now. Freshers with solid Spring Boot knowledge earn Rs 5–8 LPA at companies like TCS Digital, Infosys, Wipro, and Pune-based product companies (AmbitionBox 2025). Mid-level Java developers with 3–5 years of Spring Boot, REST API, and microservices experience earn Rs 12–22 LPA. Senior engineers at fintech, healthtech, and enterprise software companies command Rs 25–40 LPA. Specific companies actively hiring Java Spring Boot engineers in Pune include Tata Technologies (Hinjewadi), KPIT Technologies (Kharadi), Bajaj Finserv Tech, Persistent Systems, and Zensar. The AI-powered hiring wave means Java engineers who also understand Spring AI, LLM API integration, or cloud-native deployment (AWS/Azure) command significant premiums. ABC Trainings covers the full Advanced Java progression from JDBC through Servlets, JSP, Hibernate, Spring Boot, and REST APIs. Centers in Wagholi, Hadapsar, CIDCO Aurangabad, Osmanpura, and Sangli. Call +91 7039169629 to book a free demo.

Maharashtra's Chief Minister Yuva Karmadharak Prakalp Yojana (CMYKPY) provides Rs 6,000–10,000 monthly stipends to eligible youth during skill training. ABC Trainings is an approved CMYKPY center — enroll in our Advanced Java and Full Stack program and offset training costs with government support. Ask about PMKVY 4.0 eligibility as well when you call our counselors.

FAQs

Should I learn Spring MVC or Spring Boot first for a Java job?

Learn Spring Boot first. Spring MVC is the web layer within the larger Spring Framework, and Spring Boot builds on top of it with auto-configuration that removes setup overhead. Starting with Spring Boot lets you build working REST APIs quickly, which motivates continued learning. Once you understand how Spring Boot works, going deeper into Spring MVC internals (DispatcherServlet, ViewResolver, HandlerMapping) makes much more sense. Most job descriptions asking for Spring MVC skills are fine with Spring Boot — they are the same ecosystem.

Is Spring Boot enough to get a Java developer job at TCS or Infosys?

Spring Boot knowledge significantly improves your chances but is rarely sufficient alone. Most entry-level Java roles at TCS Digital, Infosys BPM, and product companies also expect basic understanding of: database operations (JDBC or Spring Data JPA), REST API design principles, version control with Git, and basic SQL. Spring Security knowledge is a strong differentiator. A project demonstrating a complete CRUD REST API with Spring Boot, Spring Data JPA, and JWT authentication — committed to GitHub — is more persuasive than course certificates alone.

What is the difference between Spring Boot and Spring Framework?

Spring Framework is the broader ecosystem: Spring Core (dependency injection), Spring MVC (web), Spring Data (database), Spring Security (auth), Spring Cloud (microservices) — each a separate module you configure and wire together. Spring Boot is a tool built on top of Spring Framework that provides auto-configuration and convention-over-configuration, so you spend less time on setup and more on business logic. Spring Boot does not add new features to Spring — it makes using Spring faster and easier. When people say Spring Boot they mean Spring Framework plus Spring Boot's auto-configuration layer.

How much do Java Spring Boot developers earn in Pune?

Java Spring Boot developers in Pune earn Rs 5–8 LPA at fresher to 1-year-experience level. With 3 years of Spring Boot, REST API, and microservices experience, that typically rises to Rs 12–18 LPA. Senior engineers with 5+ years including Spring Cloud, Kubernetes, and cloud deployment earn Rs 20–35 LPA in the Pune market (AmbitionBox, Glassdoor India 2025). Companies actively hiring in Pune's Hinjewadi, Kharadi, and Viman Nagar corridors include KPIT Technologies, Persistent Systems, Tata Technologies, Bajaj Finserv Tech, and Zensar Technologies.