Publicis Groupe

Company Description

We’re looking for a Senior Java Engineer to join a large-scale financial services platform in the middle of an active Java modernization journey. In this role, you’ll help migrate and evolve legacy systems toward modern Java (17/21) and cloud-native architectures on AWS, working on performance-critical, secure, and highly scalable services that run in production at scale.

Overview

Your Impact

• Join a large-scale financial services platform, supporting business-critical systems with high standards of reliability, security, and performance.
• Play a key role in the ongoing modernization of enterprise Java applications, including:
  • Migrating legacy Java services to modern Java versions (Java 17 / Java 21)
  • Refactoring existing codebases to improve scalability, performance, and maintainability
  • Contributing to architectural evolution toward modern, cloud-native patterns
• Design and enhance high-performance backend systems, supporting both new features and platform evolution.
• Collaborate directly with senior client stakeholders in a highly autonomous, client-facing environment.
• Contribute to platform stability by participating in production-related activities, while keeping development and modernization as the primary focus.

Qualifications

Your Skills and Experience

• Strong hands-on experience with Java in enterprise-scale systems, ideally within regulated or high-availability environments.
• Proven experience working with modern Java versions, including Java 17 and Java 21.
• Solid understanding of Core Java fundamentals, including:
  • Java Collections Framework (List, Set, Map, concurrency-aware collections)
  • Object-oriented principles and enterprise design patterns
• Strong background in concurrency and multithreading, including:
  • ExecutorService, thread pools, synchronization strategies
  • Designing thread-safe, high-performance systems
• Experience optimizing backend performance across:
  • REST APIs
  • SQL queries and data access layers
  • Microservices interactions and data processing flows
• Strong understanding of REST API concepts, including:
  • HTTP methods, status codes, idempotency
  • API versioning, error handling, and performance considerations
• Hands-on experience implementing security best practices, including:
  • Authentication and authorization with Spring Security
  • OAuth and JWT
• Proven experience in JVM analysis and tuning, including:
  • Memory management and garbage collection
  • Thread dumps vs. heap dumps: when to use each and how to analyze them
  • Performance troubleshooting using tools such as JConsole, JVisualVM, or similar
  • Understanding and practical use of JMX
• Strong debugging skills, including:
  • Local debugging and remote debugging of Java applications
  • Structured debugging methodologies for production and non-production environments
• Familiarity with basic Unix/Linux commands for troubleshooting and system inspection.
• Solid understanding of build and dependency management, including:
  • Maven concepts (lifecycle, dependencies, plugins, profiles)
• Familiarity with NoSQL databases, with MongoDB preferred.
• Understanding of event-driven architectures, including Kafka or similar messaging platforms.
• Experience working in AWS-based environments (strong plus), with exposure to multi-cloud or hybrid cloud environments as a bonus.
• Strong communication skills, able to explain technical decisions and findings clearly in discussions with senior stakeholders.

Set Yourself Apart With

• Experience modernizing enterprise Java platforms in financial or regulated industries.
• Demonstrated JVM tuning and performance optimization work.
• Background designing high-throughput, secure, event-driven backend systems.
• Exposure to cloud-native, multi-cloud, or hybrid architectures.
• Comfort leveraging AI tools to improve engineering productivity.
• Experience working directly with senior stakeholders in client-facing roles.