Senior Java Developer

About the role

N-iX is looking for a Senior Java Developer to join a long-term modernization initiative for a large US-based provider of marketing, packaging, print, and supply chain services serving Fortune-level clients worldwide.

You will work within the customer's European supply chain division, supporting warehousing, fulfillment, kitting, and packaging operations for global brands in electronics, medical devices, and consumer products. The main stakeholder is a Software Development Manager who originally built the system and remains deeply involved in its technical evolution.

About the Project

The project focuses on a customer-facing web portal that has been operating successfully for over two decades. The portal enables customers, suppliers, and partners to:

- View inventory, goods, and shipment reports

- Exchange files securely

- Submit forecasts and operational data

- Access supply chain information

The system has been in maintenance mode for several years and now requires a strategic technology uplift to address security vulnerabilities and ensure continued support for the next 5–7 years. This is not a rewrite project. The goal is a cost-effective modernization of the existing platform while preserving business-critical functionality.

Technology Stack

- Java 8

- Struts 1.1

- STXX (XML/XSLT)

- Apache Tomcat 9

- Apache HTTP Server

- Linux

- Ant

- Azure DevOps

Data & Integrations:

- Microsoft SQL Server

- Oracle Database

- Stored Procedures

- LDAP

- SFTP

- Email integrations

Application Size:

- 200,000+ lines of Java code

- Monolithic architecture

- No automated test coverage currently in place

Responsibilities

- Lead and execute the migration of a large legacy Java application

- Upgrade Java versions and modernize the framework stack

- Perform migration from javax to jakarta

- Upgrade dependencies and address security vulnerabilities

- Analyze and refactor legacy code where required

- Create unit and integration tests for existing functionality

- Support regression testing activities

- Collaborate closely with the customer’s technical stakeholders

- Deliver early security improvements and test coverage for critical business flows during the initial project phase

Requirements

Must Have

- 5+ years of commercial experience with Java

- Proven experience working with Struts 1.x

- Experience with Java version upgrades and/or framework migration projects

- Strong knowledge of Apache Tomcat and Linux environments