Hashtech Systems

About the Role :We are looking for an experienced Senior Java Developer to join our team and contribute to the development and refactoring of our Point of Sale (POS) application based on OCPP 1.6 standards. This is a desktop-based application developed in Java 8, primarily focusing on multi-threading, collections, and robust exception handling.The ideal candidate will have strong expertise in core Java, experience working with IoT communication interfaces (COM, Serial, Ethernet), and familiarity with WebSocket-based JSON messaging. You will play a key role in enhancing existing modules, improving code quality, and contributing to new application development initiatives.Key Responsibilities :- Design, develop, and maintain desktop-based POS applications using Java 8.- Work on OCPP 1.6 protocol communication using WebSocket and JSON.- Implement and optimize multi-threaded modules for real-time device communication.- Refactor legacy code to improve maintainability, performance, and scalability.- Collaborate with cross-functional teams to plan and execute new application development.- Handle COM port, serial, and Ethernet communication with IoT devices.- Perform unit testing using JUnit and participate in code reviews.- Manage source code and tasks using Git, Jira, and Maven in a Windows development environment.- Follow Agile methodologies for sprint-based development cycles.Technical Skills Required :- Strong proficiency in Core Java (Java 8) - multi-threading, collections, exception handling.- Hands-on experience with Swing for desktop UI development.- Experience with WebSocket and JSON for backend communication.- Understanding of OCPP (Open Charge Point Protocol) - preferred but not mandatory.- Familiarity with IoT communication protocols (Serial, COM, Ethernet).- Experience with JUnit, Git, Jira, and Maven.- Exposure to code refactoring and improving legacy systems.- Working knowledge of Agile/Scrum development processes.Good to Have :- Exposure to JavaScript for front-end logic or scripting.- Experience with new application design and architecture planning.- Knowledge of network protocols and device-level debugging.Soft Skills :- Strong analytical and problem-solving skills.- Excellent communication and teamwork abilities.- Ability to work independently and mentor junior developers.- High attention to detail and a passion for clean, maintainable code.Why Join Us- Opportunity to work on cutting-edge OCPP and IoT-based POS systems.- Be part of a team driving major code refactoring and modernization.- Contribute to new application initiatives in a collaborative environment. (ref:hirist.tech)