Janaka Premathilaka

Senior Full‑Stack Java Engineer

I build rock‑solid enterprise Java systems and lead them into the AI era. With 21+ years delivering mission‑critical banking and public‑sector software, I’m known for calm, dependable execution. I steady teams, cut through noise, and get results—no shortcuts. I bridge proven enterprise tech with practical AI to create scalable solutions.

Specialised in Java, Spring Boot, Oracle SQL and distributed systems, I’ve architected high‑throughput platforms and mentor teams across Sri Lanka, Belgium, UK and Switzerland.

Contact Me
Janaka Premathilaka
21+
Years Experience
40+
Enterprise Projects
100%
Success Rate
30%
Avg Performance Gain

Core Values

These principles guide my work and leadership.

Innovation

Driving new ideas from LLMs, LangGraph & RAG to streamline solutions.

Collaboration

Mentoring teams, aligning stakeholders, and fostering a culture of trust.

Reliability

Delivering resilient systems with uptime, stability and clear accountability.

Continuous Learning

Always evolving with the latest in AI, cloud, and software practices.

Results

Solving real problems, improving performance and achieving measurable impact.

About Me

After earning my BSc in Computer Science in Sri Lanka, I began my career building enterprise software in a private bank in Colombo. Over the next two decades I delivered critical systems across Europe creating e-procurement solutions for the European Commission in Belgium, architecting wealth-management platforms, and leading mission‑critical teams through the UBS–Credit Suisse merger in Switzerland and United Kingdom.

My passion lies in designing scalable architectures with Java, Spring Boot and Oracle SQL, while exploring the frontier of AI and automation with LangChain, RAG, OpenAI, LangGraph(with Python) and Kafka. I'm a hands-on leader who mentors teams, simplifies complexity, and transforms ideas into high-impact solutions.

Experience

UBS / Credit Suisse

Sr. Full‑Stack Solution Engineer

Jan 2018 – Present, Zurich, Switzerland

  • Led delivery of six enterprise applications during the UBS–Credit Suisse merger, ensuring zero major incidents.
  • Built a high‑performance Master Data Management platform from scratch to unify consumer data across global systems.
  • Developed dynamic consumer portals and case‑management tools with real‑time streaming using Kafka and GraphQL.
  • Introduced RAG‑powered intranet search and data‑analysis services with LangGraph & AutoGen, increasing productivity.
  • Maintained calm leadership under pressure, resolving critical incidents and guiding teams through complex migrations.
  • Architected a microservices platform for wealth‑management, for 3k+ daily users.
  • Designed high‑throughput event streaming pipelines with Kafka and GraphQL to power real‑time analytics.
  • Implemented RESTful APIs and responsive UI using React and Spring, improving user engagement and scalability.
  • Mentored a cross‑functional team, established coding standards and streamlined CI/CD with Jenkins.
Java 17Spring BootOracle SQLKafkaGraphQLLangChainLangGraphReactKafkaGraphQLJenkinsDocker

European Commission

Sr. Full‑Stack Java/JEE Developer

Jun 2011 – Jan 2018, Brussels, Belgium

  • Designed and developed an e-procurement system that contributed to 40% of the department’s total revenue.
  • Designed Developed microservices and integration patterns using JEE, SOAP/REST and enterprise messaging.
  • Implemented JBPM workflows for complex procurement processes, improving process efficiency.
  • Collaborated with cross‑border teams to ensure compliance with EU procurement standards.
Java EEAngularJBPMSOAOracle SQL

Skills & Tech Stack

Languages & Back‑End

Java 17, Spring Boot, Spring Cloud, JPA/Hibernate, Node.js, GraphQL.

Front‑End & UI

React, Angular, TypeScript, Tailwind CSS, HTML5, CSS3.

Databases & Cloud

Oracle SQL, PostgreSQL, MongoDB, AWS, Azure, GCP.

DevOps & Infrastructure

Docker, Kubernetes, Jenkins, GitHub Actions, Terraform, CI/CD.

AI & Data

LLMs & RAG, LangChain, LangGraph, AutoGen, OpenAI SDK, Kafka, Apache Spark.

Soft Skills

Leadership, mentoring, architecture design, problem solving, stakeholder communication.

Projects & Case Studies

RAG‑Powered Chatbot

Designed a retrieval‑augmented chatbot that leverages LangGraph and vector databases to deliver context‑aware answers in enterprise environments.

Role: Architect & Developer

Tech: Python, LangChain, LangGraph, FAISS, React.

View Code

Job Research Agent

Built an AI agent that automates job research, summarises postings and matches requirements using LLMs and data analysis.

Role: Developer

Tech: Python, LangChain, GPT‑4, Puppeteer.

View Code

Real‑Time Data Streaming & Analytics

Implemented a streaming analytics platform using Kafka, Spark and React dashboards for live insights.

Role: Solution Architect

Tech: Java, Kafka, Apache Spark, React, Grafana.

View Code

DevOps CI/CD Pipeline

Created an automated CI/CD pipeline for microservices using Jenkins, Docker and Kubernetes to enable seamless deployments.

Role: DevOps Engineer

Tech: Jenkins, Docker, Kubernetes, Helm.

View Code

Technical Blog & Writing

Share deep dives into Java, Spring Boot, AI & microservices on my blog, demystifying complex topics.

Role: Author

Tech: Hugo, Markdown, Netlify.

Read Blog

Education & Certifications

BSc Computer Science

University of Sri Jayewardenepura

1999 – 2003

Major in Computer Science with minors in Statistics and Mathematics.

Master’s in Computer Engineering

University of Moratuwa

2007 – Present (In progress)

Researching distributed systems and AI integration.

Agentic AI Engineering (2025)

Complete Agentic AI Engineering Course

2025

Comprehensive course on building AI agents with LLMs and RAG techniques.

Certifications & Awards

  • CKA – Certified Kubernetes Administrator (2024)
  • AWS Solutions Architect Associate (2023)
  • Sun Java Certifications (SCJP, SCBCD, SCEA1)

Get in Touch

Interested in working together or learning more? Feel free to reach out.

Email

[email protected]

LinkedIn

linkedin.com/in/janakapremathilaka

GitHub

github.com/Janaka2

Get in Touch

I am always available to connect. Use any of the following methods to reach me.

+41 76 224 84 45
WhatsApp
[email protected]
LinkedIn
GitHub