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Walmart Core System Performance Overhaul

Portfolio Best Practices

When creating your own portfolio entries, include specific metrics, your individual contributions, and the technical decisions that drove results — as shown below.

Project Summary

Company: Walmart Location: Sunnyvale, CA Duration: Apr 2025 – Aug 2025 Role: Software Developer

Key Outcomes:

  • 20% performance boost via JDK 17 migration (completed in 6 weeks)
  • 15% improvement in startup time via Spring Boot 2.5→3.3 upgrade
  • Significantly improved maintainability and reliability of a core system
  • New flagship feature delivered using Java 17, Spring Boot, GraphQL, and REST APIs

Challenge

A core production system at Walmart was running on an aging JDK version and an outdated Spring Boot release. This created performance bottlenecks, slowing response times and increasing startup overhead. Upgrading these systems required careful planning to avoid regressions in a high-traffic production environment.

Additionally, the team needed new features delivered on a modern stack while developer productivity had to keep pace with fast-moving requirements.

Approach

JDK 17 Migration: Analyzed the existing codebase for deprecated APIs and compatibility issues, created a migration plan, and executed the upgrade within 6 weeks. Ran comprehensive regression testing to validate no functional regressions were introduced.

Spring Boot Upgrade (2.5→3.3): Led the upgrade of the core system, addressing breaking changes in Spring Security, Jakarta EE namespace migration, and dependency compatibility. This was a more complex upgrade given the major version jump.

New Feature Development: Designed and implemented a new feature for a flagship product using Java 17, Spring Boot, GraphQL, and RESTful APIs — delivering in an agile SDLC with iterative sprints.

AI-Powered Developer Productivity: Leveraged GitHub Copilot, MCP server, and Qodo merge to streamline code design and review, supporting the broader team in delivering features faster.

Results & Impact

  • 20% performance boost on core system after JDK 17 migration
  • 15% faster startup time after Spring Boot 2.5→3.3 upgrade
  • Significantly improved long-term maintainability and reliability
  • New flagship feature shipped on modern Java 17 stack
  • Improved team developer productivity through AI-powered tooling

Tech Stack

  • Java 17
  • Spring Boot 3.3
  • GraphQL
  • RESTful APIs
  • GitHub Copilot / MCP server / Qodo merge
  • Agile SDLC
  • CI/CD pipelines

Additional Context

  • Timeline: 5 months
  • Role: Software Developer (individual contributor)
  • JDK migration completed in 6 weeks
  • Worked cross-functionally in an agile team

  • Want to learn more?

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