Java Full-Stack Developer with 6+ Years Experience

Ajay Kumar

Java Full Stack Developer

****.***********@*****.***• +1-314-***-**** https://www.linkedin.com/in/ajaykumar788163 SUMMARY

Java Full Stack Developer with 6+ years of experience in designing and delivering scalable enterprise applications across healthcare, banking, and finance domains using Java, Spring Boot, Microservices, Hibernate, RESTful APIs, SOA, and MVC architecture, with strong expertise in Core Java, Multithreading, Collections, Streams, and design patterns such as Singleton, Factory, DAO, and Observer. Proficient in front-end technologies including ReactJS, Angular, JavaScript, GraphQL, HTML5, CSS3, and Bootstrap, and experienced in working with relational and NoSQL databases like Oracle, MySQL, PostgreSQL, SQL Server, MongoDB, Cassandra, and DynamoDB, along with PL/SQL stored procedures and performance tuning. Skilled in implementing secure applications using OAuth2, JWT, SAML, SSL, and OpenId, integrating messaging systems such as Apache Kafka, RabbitMQ, and ActiveMQ, and developing event-driven microservices with Spring Cloud Gateway. Hands-on experience with JUnit, Mockito, Jest, Cucumber, Postman, Swagger UI, and DevOps tools including Jenkins, Git, Maven, Gradle, SonarQube, following Agile/Scrum SDLC to deliver high-quality, maintainable, and business-aligned solutions. SKILLS

• Languages: Java, SQL, PL/SQL, TypeScript, JSON, Shell Scripting, Python

• Web Technologies: ReactJS, Angular, Vue.js, GraphQL, Bootstrap, jQuery, AJAX, HTML, CSS, JavaScript, Thymeleaf

• Databases: Oracle, MySQL, PostgreSQL, SQL Server, DB2, MongoDB, Cassandra, DynamoDB

• Java Technologies (J2EE): Core Java, Spring Boot, Spring MVC, Spring Security, Struts, Servlets, JSP, Spring Cloud

• ORM Frameworks: Hibernate, JPA, Spring Data JPA, Spring JDBC, Spring Data REST

• Web Servers: Apache Tomcat, JBoss, WebLogic, WebSphere

• Testing Frameworks: JUnit, Mockito, TestNG, EasyMock, Cucumber, Protractor, Jasmine, Karma, Mocha, Jest, Chai.

• Web Services: RESTful APIs, SOAP, Swagger UI, Postman, SOAP UI

• Version Control Tools: Git, SVN, CVS

• Methodologies: Agile (Scrum), Waterfall

• DevOps & Build Tools: Maven, Gradle, Jenkins, Docker, Kubernetes.

• Cloud Technologies: AWS (EC2, S3, RDS, Lambda), Azure (Blob Storage, App Services, Functions)

• Operating Systems & IDEs: Windows, Linux, IntelliJ IDEA, Eclipse, VS Code, Postman, SoapUI Work EXPERIENCE

Vanguard Aug 2024 – Present

Java Full Stack Developer

• Participated in Agile development, including sprint planning, backlog grooming, and retrospectives, delivering enhancements to the investment portal based on stakeholder feedback and goals.

• Designed and implemented Spring Boot Microservices, reducing API response time by ~30% and enabling independent deployment of 8+ services.

• Developed backend logic using RESTful architecture, utilizing Spring Boot annotations, service layers, and repository interfaces to ensure efficient data flow and high-performance responses.

• Created responsive UI components using Angular, integrating HTML, CSS, JavaScript, and Bootstrap, delivering a modern and dynamic user experience across desktop and mobile platforms.

• Connected Angular modules with RESTful APIs, ensuring secure, stateless client-server communication, real-time market data rendering, and consistent error handling with standardized responses.

• Implemented ORM using Hibernate, mapping Java entities to Oracle tables, optimizing CRUD operations, and utilizing HQL and criteria queries to handle complex investment-related data queries.

• Used JSON for transmitting structured data between Angular and Java services, enabling smooth serialization/deserialization, improving responsiveness, and simplifying frontend-backend integration.

• Deployed and configured Spring Cloud API Gateway to centralize routing, authentication, and load balancing, improving performance and maintainability across distributed environments.

• Secured backend APIs using OAuth2, applying token-based authentication for session control and fine-grained authorization across internal components and third-party integrations.

• Tested user interfaces using Protractor and Cucumber, automating BDD-style tests and validating cross-browser compatibility to ensure UI alignment with business flows and accessibility standards.

• Created unit and integration tests using JUnit and Mockito, mocking service dependencies and achieving high code coverage for core logic within service and controller layers.

• Queried and managed structured datasets in Oracle, implementing schema designs, optimizing queries with indexes, and handling financial datasets with high precision and performance needs.

• Used MongoDB to store unstructured session and user preference data, improving personalization features and supporting hybrid data models within the investment portal application.

• Integrated Apache Kafka for real-time trade events, processing ~50K+ events/day with fault-tolerant producer/consumer architecture.

• Automated CI/CD with Jenkins, Docker, and AWS EC2, cutting deployment time from ~40 mins to 10 mins. PNC Bank Dec 2020 – July 2023

Java Full Stack Developer

• Collaborated in an Agile Scrum environment, attending daily stand-ups, sprint planning, and retrospectives while working with cross-functional teams to deliver banking features with timely updates and development.

• Designed backend systems using Spring Boot based on Microservices and Service-Oriented Architecture (SOA), improving modularity, service independence, and ease of deployment across banking components.

• Developed stateless RESTful services by integrating business logic into Spring Boot controllers and services, exposing well-structured endpoints for client-side data consumption and real-time account interactions.

• Built responsive front-end modules using ReactJS, HTML, CSS, JavaScript, and Bootstrap, creating seamless UI features such as funds transfer, account summary, and transaction history.

• Created and consumed secure RESTful APIs with proper HTTP methods, status codes, and OAuth2 token-based authentication to ensure efficient data transmission between front-end and back-end services.

• Employed Spring Data JPA for ORM, utilizing repository abstraction and custom JPQL queries to manage complex banking data stored in PostgreSQL, reducing boilerplate and simplifying database interaction.

• Structured all API requests and responses in JSON format to enable consistent serialization and deserialization between the React front-end and Java-based backend services.

• Configured Spring Cloud API Gateway to route requests between microservices, applying filters for logging, security enforcement, rate limiting, and improving observability in distributed systems.

• Implemented OAuth2-based authentication by managing access tokens and refresh tokens to provide secure access control to sensitive APIs and ensure session validity in banking workflows.

• Achieved 85%+ code coverage using JUnit & Mockito and reduced regression defects by 40%.

• Performed ReactJS front-end testing using Jest, Mocha, and Chai to validate UI components, event handlers, and state transitions, reducing regression issues across deployments.

• Leveraged PostgreSQL for structured banking data storage, optimizing database design with indexes, foreign keys, and queries to support high concurrency and transactional accuracy.

• Used DynamoDB for semi-structured session data, enabling high-throughput storage and real-time analytics while maintaining performance and scalability.

• Integrated Apache Kafka for publishing and consuming customer events and automated CI/CD pipelines using Jenkins with Git and Gradle, accelerating deployments to Azure App Services with improved consistency. Humana Jan 2019 – Dec 2020

Java Full Stack Developer

• Worked in an Agile environment with daily stand-ups, sprint planning, and backlog grooming to deliver health insurance features with quality delivery.

• Designed Microservices Architecture using Spring Boot for claims and eligibility services following SOA principles for scalability and modular deployment.

• Built RESTful APIs using Spring Boot integrating business logic and repositories for patient validation and insurance verification workflows.

• Developed responsive UI using Angular, HTML, CSS, JavaScript, and Bootstrap for fast patient lookup operations.

• Integrated third-party and pharmacy benefit systems via REST APIs for real-time patient and claim data synchronization.

• Wrote custom SQL queries and Spring JDBC row mappers for complex healthcare data in SQL Server to improve performance.

• Configured Spring Cloud Gateway for routing, logging, token validation and secured endpoints using OAuth2 security.

• Implemented testing with JUnit, Mockito, Karma, Jasmine, Cucumber, and Citrus for unit, UI, and BDD API automation.

• Used Apache Kafka for event-driven processing of patient and claims data to improve scalability and fault tolerance.

• Automated application deployment to Amazon EKS (Elastic Kubernetes Service) via Jenkins CI/CD pipelines, achieving faster and consistent releases. EDUCATION

Masters of Science in Computer Science

Lewis University, Romeoville, Illinois

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