Harry is available for hire
Hire HarryHarry Sun
Verified Expert in Engineering
Java Developer
Melbourne, Victoria, Australia
Toptal member since December 13, 2014
Bio
Harry is a senior GenAI and full-stack engineer with 28+ years of experience in Java, Python, TypeScript, and cloud technologies. He bridges the gap between AI prototypes and production services. Recently, he has focused on applied LLM delivery, including RAG, AI search, and human-in-the-loop workflows for insurance and CRM. Through OpenClaw research, Harry transforms complex projects into autonomous, closed-loop systems with robust API boundaries, observability, and production guardrails.
Portfolio
Ayla
Generative Artificial Intelligence (GenAI), Python, Deno, Supabase, Java
Directed Electronics Australia
Amazon Web Services (AWS), React, JOOQ, Spring Boot, Spring, Java, SQL, Node.js...
Odecee (Cognizant)
Gradle, Camel, Spring Boot, Sysl, Oracle, Docker, Redux, React, Spring, Java...
Experience
- Java - 10 years
- Generative Artificial Intelligence (GenAI) - 6 years
- Amazon Web Services (AWS) - 3 years
- Python - 3 years
- TypeScript - 3 years
- Large Language Models (LLMs) - 3 years
- Lovable - 1 year
- Supabase - 1 year
Work Experience
Solution Architect
2018 - PRESENT
Ayla
- Owned solution architecture for a portfolio of applied-AI services across bill extraction, personal finance chat, eCommerce search, real estate listing workflows, AI-assisted CRM, and insurance claim automation.
- Led the bill extraction migration from AutoML/Document AI and vendor-specific parsing to LLM-powered extraction, improving accuracy from roughly 78% to about 95% and reducing new supplier bill integration from five days to one day.
- Implemented a staged GenAI CRM pipeline for a real estate admin portal, transforming emails, screenshots, and email threads into issues, solution plans, draft replies, FAQ candidates, customer memory, and stage-level diagnostics.
- Maintained the core API and integration platform behind these workflows, covering billing, document processing, notifications, cloud storage, provider APIs, validation, deployment, and operational guardrails.
- Built AI search and listing automation components, including hybrid semantic/keyword product retrieval, WooCommerce index synchronization, marketplace listing generation, and GPT-assisted real estate XML normalization.
Technologies: Generative Artificial Intelligence (GenAI), Python, Deno, Supabase, Java
Senior Software Engineer
2018 - 2026
Directed Electronics Australia
- Architected and built a beacon server for senior-care pendant tracking and monitoring using Java 17, Spring Boot, Netty, Redis, RabbitMQ/AMQP, MQTT, and PostgreSQL.
- Refactored beacon server to use stream queues, which improved overall performance by 50% in EC2 update and OTA process, and increased concurrent device volume from around 5,000 to around 20,000 on a typical t3 small EC2 instance.
- Built Balena Cloud and Open Balena, an open-source solution for containerizing IoT devices on the cloud.
- Created a few website/demo side projects from scratch, based on AWS API Gateway, Lambda, CloudFront, React, Redux, Saga, and Ant Design. Trained team members and managed projects.
- Managed an offshore team on a few projects, including APIs (Java, Spring Boot, and jOOQ), mobile apps (React Native), and admin consoles (React and Ant Design).
Technologies: Amazon Web Services (AWS), React, JOOQ, Spring Boot, Spring, Java, SQL, Node.js, Python, CI/CD Pipelines, Back-end
Senior Software Engineer
2017 - 2018
Odecee (Cognizant)
- Developed a product recommendation microservice from scratch using JDK11 and a rules engine for a project at ANZ.
- Created a microservice product for small businesses at ANZ utilizing Java, Spring, Spring Boot, Apache Camel, React, Redux, Saga, and OpenShift.
- Built the BOX and SBOLA projects using Java/Spring Boot microservices and a Groovy/Spock rules engine for product recommendation and retail banking workflows, integrating Hibernate, Redis, Apache Camel, OpenShift, React, Redux, Jest, and Cucumber.
Technologies: Gradle, Camel, Spring Boot, Sysl, Oracle, Docker, Redux, React, Spring, Java, SQL, Node.js, Back-end
Software Engineer
2014 - 2017
IRESS
- Created and implemented a TypeScript code analysis tool to generate API document and enforce coding rules in the data layer.
- Designed and implemented widget plugins, item picker, account picker and account explorer, and portfolio picker. The account picker and explorer can support loading 110,000 accounts.
- Designed and developed the search feature/component in the front end.
- Built the data layer for a notification and alert feature.
- Improved security and performance of the application, also enhanced the deployment tool using C# and .NET.
Technologies: Knockout (Knockout.js), TypeScript, JavaScript, Node.js, Back-end
Contractor Developer
2014 - 2014
Epictenet
- Resolved a blocker issue by using AM/VO instead of REST URL data control to deal with complex scenarios in ADF in my first two weeks on this project.
- Worked out all functions of my documents by using a library based on RIDC protocol to access a UCM file repository at the back end and ADF task flows with beans at the front end.
- Improved the UI framework. Continuously constructed some handy utility classes to handle mapping between POJO and JSON based on Apache BeanUtils and Jettison.
- Introduced a straightforward and flexible approach to call RESTful APIs through the ADF front end.
Technologies: Web App Testing, REST, jQuery UI, jQuery, Universal Content Management (UCM), Oracle Fusion Middleware, Jersey, JAX-RS, JPA, Enterprise Java Beans (EJB), JDeveloper, ADF, Jakarta EE (Java EE or J2EE), Back-end
Project Lead, Development Manager
2011 - 2014
Oracle (China) Software Systems Co., Ltd.
- Designed, developed, and maintained the Fusion HCM payroll Australia localization on several hands-on UI and reporting projects.
- Managed a sample implementation project for Fusion HCM HR and payroll China localization using a scrum approach and operating as scrum master.
- Received an employee recognition award in May 2013.
Technologies: Oracle PL/SQL, XML, Oracle Business Intelligence Enterprise Edition 11g (OBIEE), Oracle Fusion HCM, WebCenter, JDeveloper, JUnit, ADF, Jakarta EE (Java EE or J2EE), SQL, Back-end
Project History
Machine Learning
https://github.com/harrysun2006/17_machine_learningAssignments and practice project from an online course I took: Machine Learning, facilitated by Stanford University and presented by Andrew Ng.
Neural Network for Machine Learning
https://github.com/harrysun2006/17_neural_networksAssignments and practices from an online course I took: Neural Network for Machine Learning, facilitated by the University of Toronto and presented by Geoffrey Hinton.
Demo Portal for SalaryMaster Corporation
A demo portal built based on React, Redux, and Ant Design with a back-end stack including Java, Spring, jOOQ, PostgreSQL, AWS, and other technologies. Used a GitLab pipeline, AWS CloudFormation, CloudFront, RDS, and CodeDeploy to drive the CI/CD.
Website for EquityMaster
A website built upon React, Redux, and Ant Design on the front end and AWS API Gateway, Lambda, and SES on the back end. Also used a GitLab pipeline, Docker, AWS CloudFormation, CloudFront, and S3 in deployment.
Idea System (J2EE)
A web application (idea system) for Samsung Semiconductor (Suzhou) Co., Ltd. from business analysis till to user training, developed by myself. This application is integrated with the user’s existing SSO and email system.
An Evaluator (Flash ActionScript)
Expression evaluator with context in Flash ActionScript.
Education
1993 - 1997
Advanced Degree in Mathematics
Nanjing University - Nanjing, China
Certifications
AUGUST 2017 - PRESENT
Neural Networks for Machine Learning
University of Toronto | via Coursera
AUGUST 2017 - PRESENT
Machine Learning
Stanford University | via Coursera
Skills
Libraries/APIs
JOOQ, React, jQuery, Node.js, jQuery UI, JAX-RS, Google API, Google Maps
Tools
Docker Compose, JDeveloper, Oracle Business Intelligence Enterprise Edition 11g (OBIEE), Gradle, Microsoft Visual Studio, n8n
Languages
TypeScript, Java, JavaScript, SQL, Python, Rust, XML, Sysl, C, PowerBuilder, C++, Flash ActionScript
Frameworks
Netty, JPA, ADF, Spring, JUnit, Jersey, Spring Boot, Knockout (Knockout.js), Redux, Camel
Platforms
Amazon Web Services (AWS), Docker, Oracle, Google Cloud Platform (GCP), Jakarta EE (Java EE or J2EE), WebCenter
Storage
PostgreSQL, Oracle PL/SQL, Redis, MongoDB
Paradigms
REST, Test-driven Development (TDD), Test Automation
Other
Software Development, Back-end, WebSockets, CI/CD Pipelines, Lovable, Supabase, Generative Artificial Intelligence (GenAI), Oracle Fusion Middleware, Universal Content Management (UCM), Web App Testing, Oracle Fusion HCM, Machine Learning, Enterprise Java Beans (EJB), OpenClaw, ClaudeCode, Deno, Applied Mathematics, Large Language Models (LLMs)
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