Senior Java Engineer – Terminal Emulation & Host Connectivity

About the role

HWS Technologies is seeking a Senior Java Engineer to own the continued development and modernisation of HWS J-Term, a mature Windows terminal emulator used in mission‑critical client environments. You will work deep in the stack on terminal protocols, networking, concurrency, rendering, security and native Windows integration.

Key responsibilities

• Perform root‑cause analysis and troubleshooting across protocol, rendering and API layers.
• Build automated test coverage for protocol implementations.
• Identify and remediate security vulnerabilities, especially around TLS, SSH and credential handling.
• Incrementally modernise the architecture and build system while preserving backward compatibility.
• Analyse customer issues using network logs and technical diagnostics.
• Contribute to the maintainability, reliability and security of the product.

Required profile

• 7+ years of professional Java experience, including at least 3 years with mature or legacy systems.
• Strong knowledge of multithreading, socket programming and low‑level byte/bit processing.
• Confidence working with AWT/Swing and the Event Dispatch Thread.
• Experience with TLS/JSSE, SSH and Windows‑based development.
• Basic knowledge of JNA/JNI and willingness to improve CI pipelines.
• Practical experience in legacy refactoring and characterisation testing.

Required skills

• Java (core, multithreading, socket APIs)
• AWT/Swing UI development
• TLS/JSSE and SSH protocols
• Windows integration, JNA/JNI
• Maven and Ant build tools
• CI/CD pipeline setup
• Legacy code refactoring, characterisation testing
• IBM 3270 / 5250 or DEC VT protocols (nice to have)
• EBCDIC, HLLAPI, terminal emulation concepts
• Reading C/C++ code, COM/DDE, Eclipse RCP/OSGi (nice to have)

What we offer

• Real ownership of a unique, established product.
• Opportunity to solve challenging low‑level Java and networking problems.
• Scope to modernise a mature system without sacrificing compatibility.
• Improvement of security, testing and engineering practices.
• Collaboration with an experienced international technology team.