Hire the Best J2SE Specialists

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Divyansh M.

Jodhpur, India

$25/hr
5.0
3 jobs

When your backend is breaking under load, your microservices are drifting, or your APIs aren't talking to each other, I'm the engineer who fixes it without breaking everything else. I build and maintain production-grade systems using Java Spring Boot, React, Node.js, and cloud-native infrastructure. My work runs at scale: Microservices handling 20,000+ concurrent users (Spring Boot + Kafka + Kubernetes) REST APIs serving 50,000+ monthly users with clean contracts and error handling CI/CD pipelines on GitHub Actions and Jenkins with automated test gates AWS deployments (EC2, EKS, ECR, ALB) with zero-downtime rolling releases Elasticsearch integration cutting search response times from 800ms to under 200ms OAuth 2.0 + TLS security reducing vulnerability incidents by 70% What I help with: Java Spring Boot microservices, build, fix, optimize React frontend connected to backend APIs Kafka event-driven architecture Docker + Kubernetes deployments AWS cloud infrastructure CI/CD pipeline setup and maintenance API integration and debugging 100% Job Success · Rising Talent · 0-4hr response time If your system is slow, broken, or needs scaling, message me and I'll tell you exactly what's wrong.

  • Java
  • Spring Boot
  • React
  • JavaScript
  • Next.js
  • PostgreSQL
  • MySQL
  • Docker
  • RESTful API
  • MongoDB
  • Redis
  • API Integration
  • Apache Kafka
  • Kubernetes
  • AWS CodeDeploy
  • GitHub
  • Jenkins
  • CI/CD
  • Microservice
  • TypeScript
Yatin S.

Fazilka, India

$16/hr
4.9
8 jobs

Senior Java Developer | Spring Boot Expert | Microservices | AWS | AI-Assisted Development I help businesses build scalable backend systems, enterprise APIs, and cloud-native applications using Java, Spring Boot, Hibernate, Microservices, AWS, PostgreSQL, MongoDB, Kafka, and modern AI-assisted development tools. With strong experience in Java backend development, I specialize in: ✔ Java 8/11/17+ Application Development ✔ Spring Boot & Microservices Architecture ✔ REST API Development & Third-Party Integrations ✔ Hibernate / JPA / Performance Optimization ✔ PostgreSQL, MySQL, MongoDB ✔ Event-Driven Systems (Kafka, Messaging) ✔ AWS, Docker, Kubernetes ✔ Secure APIs (Spring Security, JWT, OAuth) ✔ Legacy System Modernization ✔ Full-Stack Development (Angular, Node.js) ✔ AI-Assisted Development using ChatGPT, Claude AI, and GitHub Copilot What I Deliver • Production-grade Java Spring Boot applications • High-performance backend APIs • Scalable microservices architectures • Enterprise integrations and data-driven systems • Performance tuning, debugging, and system optimization • Cloud-ready deployments on AWS Why Clients Hire Me I focus on clean architecture, maintainable code, and practical solutions not overengineering. By leveraging modern AI tools like ChatGPT, Claude AI, and GitHub Copilot, I accelerate development, improve code quality, generate documentation, and speed up debugging while ensuring every solution is thoroughly reviewed and production-ready. Whether you need: • A Spring Boot developer for a SaaS platform • A Java backend developer for APIs, integrations, or cloud applications • Help with microservices, performance optimization, or legacy modernization • A developer who combines deep engineering expertise with AI-assisted productivity I can help. I've worked on complex backend systems involving real-time event processing, enterprise integrations, database-intensive workflows, cloud-native deployments, and event-driven architectures. If you're looking for a reliable Java/Spring Boot expert who takes ownership, communicates proactively, and delivers scalable solutions on time, let's discuss your project.

  • Java
  • Spring Boot
  • Angular
  • Java Servlet API
  • Java Collections Framework
  • Web Development
  • Spring MVC
  • MySQL
  • React
  • Node.js
  • Next.js
  • AI Development
  • Oracle
  • AWS Cloud9
  • Claude
Rushabh A.

Pune, India

$25/hr
5.0
3 jobs

I'm a Full-Stack Data with Python Java Developer with over 8+ years of industry experience. I excel in all aspects of Java application development, from design and development to deployment. I have a proven track record of building robust and Scalable applications across diverse domains. My Expertise Full-Stack Development: Java: Core Java, multithreading, OOP, Spring, Hibernate, Struts, J2EE. Frameworks & Libraries: Spring, Hibernate, JavaFX, Apache Struts. Microservices Architecture: Spring Cloud, Netflix OSS, service discovery, load balancing, tolerance mechanisms. Web Development: JSP, Servlets, RESTful APIs, Angular, React, HTML, CSS, JavaScript. Databases: MySQL, PostgreSQL, MongoDB, Redis. Testing & Debugging: JUnit, Mockito. I also use GitHub Copilot and Claude Code to deliver the best solutions. ✔ LLM integrations (OpenAI, Claude, etc.) ✔ AI-assisted workflow automation ✔ Prompt engineering & optimization ✔ RAG based enterprise search solutions ✔ AI code acceleration using tools like Cursor ✔ Designing AI-ready Microservices architecture Java Solution Architect: Designing scalable solutions with Java, Spring, Hibernate, and microservices. DevOps: Cloud setup, infrastructure management, CI/CD. Proficient in AWS (Lambda, EC2, S3, Redshift, SageMaker, Cognito) and GCP (VMs, Google cloud storage). Domain Experience: Insurance, finance, healthcare, e-learning, e-commerce, travel, real estate, logistics, supply chain, social networking, and education. CRM and ERP systems.

  • Java
  • Spring Boot
  • Spring Batch
  • Python
  • TypeScript
  • Microservice
  • MySQL
  • PostgreSQL
  • API
  • Google Analytics
  • ETL
  • Angular
  • Data Engineering
  • Angular 5
  • React
Rashu K.

Panipat, India

$7/hr
5.0
2 jobs

Hi! I’m Rashu, an Expert Java Back-End Developer. Are you looking for a reliable, detail-oriented back-end developer who delivers high-quality, scalable, and secure solutions? With over 5+ years of hands-on experience in Java-based backend development, I specialize in building powerful server-side applications that drive performance and growth. 🔧 Technical Skills & Tools: 🖥 Backend Development - Java, Spring Boot, Hibernate, JUnit, RESTful APIs & Microservices Architecture ☁ Cloud & DevOps - AWS (EC2, S3, RDS) 💾 Databases & Version Control - SQL, MySQL, PostgreSQL Git, Bitbucket 🏥 Domain Experience: *Healthcare: Developed a complete Hospital Management ERP Software used for streamlining patient records, billing, pharmacy, and more. Banking: Worked on secure, transaction-heavy systems with robust authentication and compliance. *Voice Testing Applications: Built reliable and performance-oriented back-end components for voice-based testing platforms. ✅ Why Work With Me: *100% commitment to client satisfaction *Known for being detail-oriented, reliable, and deadline-driven *Clean, maintainable code with proper testing using JUnit *Strong communication skills and proactive problem-solving 📩 Let’s Get Started! Let’s build something great together. I’m here to bring your project to life with efficiency and precision. Send me a message and let’s talk about how I can help! **This is not a company or agency account. Only the profile name is of my firm's name but I am an Independent Freelancer and all the information is about me only.

  • Back-End Development
  • Spring Boot
  • Hibernate
  • JUnit
  • RESTful API
  • Microservice
  • DevOps
  • AWS Cloud9
  • MySQL
  • PostgreSQL
  • Git
  • Bitbucket
  • Java
  • Version Control
  • Cloud Architecture
Samson A.

Addis Ababa, Ethiopia

$25/hr
5.0
2 jobs

Backend & API Integrations Engineer — Java/Spring Boot, Node.js/NestJS, and the third-party integrations most teams don't want to touch (QuickBooks, Xero, payments, accounting). I build and stabilize reliable backends: clean REST APIs, microservices, and integrations that actually stay in sync. 8+ years of backend experience and 2,700+ hours delivering systems that handle high traffic and financial/inventory workflows. Where I help most: - API & platform integrations — QuickBooks Online & Xero (OAuth2, tokens, webhooks, sync, reconciliation), cXML purchase-order flows, and payment/accounting platforms - Microservices — designed and maintained 32+ services with CI/CD + Docker, improving uptime and cutting deployment time - Backend rebuilds — refactored legacy systems into scalable services with measurably higher throughput - Security — JWT, Spring Security, and Auth0 authentication/authorization - Reliability — async processing with Kafka/SQS, idempotency, retries, and rate limiting, backed by tests (JUnit, Mockito, Testcontainers) Tech I work with: Java, Spring Boot, Node.js, NestJS, Python, PostgreSQL, MySQL, MongoDB, MariaDB, Redis, DynamoDB, Docker, Apache Kafka, AWS SQS, REST, gRPC. How I work: I start with a short review of your current code/architecture, then give you a clear plan, timeline, and checkpoints — so you always know what's happening and what comes next. If you're dealing with a fragile backend, a stalled integration, or you need a new API built right the first time, send me a message describing what you're trying to achieve and I'll reply with a concrete next step. — Samson

  • Java
  • Spring Boot
  • AI Development
  • Python
  • Intuit QuickBooks
  • Auth0
  • Node.js
  • API Integration
  • PostgreSQL
  • Docker
  • Apache Kafka
  • MongoDB
  • Xero
  • CI/CD
  • Amazon Web Services
Yuvaraj S.

Vellore, India

$35/hr
5.0
6 jobs

Senior Software Engineer having 8+ years of experience with the below skills • 8 years of experience in the design/development of Java/J2EE-based systems and microservice systems. • Strong working knowledge in MVC Architecture and Frameworks – Spring and Spring Boot Framework. • 8+ Years experience in designing and developing Microservices architecture. • 8+ Years experience in Amazon Web Services • 8+ Years experience in Restful web services. • 8+ Years experience in MS-SQL, MONGO, and MYSQL Databases. • Having good working knowledge in Database related Performance engineering activities • 8+ Years experience in Docker Container and Kubernetes. • 8+ Years experience in Kafka Queuing system • Having experience with Designing, Developing, Configuring, and Testing Application environments using Java (Java, Servlets, JSP, JSTL, Java Beans, JDBC, HIBERNATE, Database Mapping, Log4j, HTML).

  • Kubernetes
  • Docker Compose
  • Spring Boot
  • Docker
  • RESTful API
  • Spring Framework
  • PostgreSQL
  • AWS Application
  • Microservice
  • DevOps
  • JavaScript
  • Kotlin
  • Apache Kafka
  • API
  • Java

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