Salary: £35,000 - 45,000 per year Requirements: We are looking for strong commercial Java development experience. We are looking for experience developing desktop applications using Swing and/or JavaFX. We are looking for a strong understanding of Core Java and object-oriented programming. We are looking for experience working within larger or long-term codebases. We are looking for strong debugging, analytical, and problem-solving skills. We are looking for the ability to work independently and take ownership of technical challenges. We are looking for the ability to think beyond individual tickets and contribute to longer-term product improvement. We are looking for strong written and verbal English communication skills. We value strong personal projects, GitHub work, or demonstrable practical coding ability highly. Experience with multithreading and concurrency would be beneficial. Experience with MySQL or SQLite would be beneficial. Experience with JasperReports would be beneficial. Experience with Git would be beneficial. Experience with file parsing and processing would be beneficial. Experience with AI-assisted development workflows would be beneficial. We prefer candidates with relevant Java desktop experience over those focused primarily on web development. We require applicants to be able to commute to our Stafford ST18 office or relocate before starting work. We require work authorisation in the United Kingdom. Responsibilities: We develop long-term desktop applications using Java and Swing, with some JavaFX where appropriate. We improve and maintain large commercial codebases. We optimise performance and troubleshoot technical issues. We design intuitive desktop user interfaces. We integrate with databases such as MySQL and SQLite. We handle file processing, reporting, and data management. We contribute ideas, innovation, and long-term technical improvements across our platform. We help guide development standards, architecture decisions, and future technical direction. We support, mentor, and where appropriate supervise other developers as our team grows. We work hands-on on software used daily in real operational environments where reliability, usability, and performance matter. We collaborate within a smaller technical team and contribute directly to product and workflow decisions. Technologies: AI Git GitHub Support Java JavaFX MySQL SQLite Swing Web Exposed Marketing More: We are Semantics 21, a multi-award-winning UK software company developing specialist desktop software used internationally within public safety and investigative environments. Our technology helps organisations process and review digital evidence more effectively, supporting work with genuine real-world impact in areas including child protection and public safety. We are growing our engineering team and hiring a Senior Java Software Engineer to work from our Stafford ST18 office, with office-based working preferred and hybrid considered depending on experience and fit. This is a full-time, permanent role with free onsite parking, flexible working hours where possible, a company pension, an employee mentoring programme, and a friendly, supportive, low-bureaucracy environment. We offer long-term stable product development work, real influence within a growing engineering team, direct involvement in technical direction, modern tooling, sensible AI-assisted development support, and opportunities for progression. last updated 21 week of 2026