Java Backend Developer

The Java Backend Developer will design, maintain, optimize, and troubleshoot high-performance backend applications supporting large user bases. The role requires deep hands-on Java expertise across Java 8, 11, 17, and 21, with a strong focus on performance engineering, load testing, database optimization, concurrency, and distributed systems. The developer will analyze and refactor existing code, identify and resolve CPU, memory, and concurrency issues, and build reliable microservices using modern containerized and distributed architectures.

Key Responsibilities

• Read, debug, optimize, and refactor existing backend codebases written across Java 8, 11, 17, and 21.
• Design and execute load-testing strategies using tools such as JMeter to evaluate system stability, performance, and bottleneck boundaries.
• Manage, tune, and optimize SQL database interactions using indexing, connection pooling, lock management, and other performance optimization techniques.
• Perform root-cause analysis of application and system issues by analyzing logs and using profiling tools such as YourKit or equivalent.
• Troubleshoot CPU spikes, memory leaks, concurrency bottlenecks, and other performance-related issues.
• Architect and maintain reliable backend components operating across load balancers, Kubernetes environments, and distributed networks.
• Apply appropriate data structures, algorithms, and Big O analysis to address latency and throughput challenges.
• Develop and deploy scalable microservices using Docker, Kubernetes, and load-balanced architectures.
• Implement and optimize caching solutions using technologies such as Redis.

Required Qualifications

• Deep hands-on Java development experience across Java 8 through Java 21.
• Expert understanding of multi-threading, thread safety, locks, and concurrent programming patterns.
• Advanced knowledge of SQL optimization, execution plans, indexing strategies, and connection pooling.
• Demonstrated experience with performance profiling and load testing using JMeter, YourKit, or similar tools.
• Experience building and deploying microservices using Docker and Kubernetes.
• Experience working with load-balanced and distributed network architectures.
• Hands-on experience with caching frameworks such as Redis.
• Strong understanding of data structures, algorithms, and time and space complexity using Big O analysis.
• Proven ability to identify and resolve memory leaks and performance bottlenecks.
• Strong root-cause analysis and troubleshooting skills for enterprise backend applications.
• Ability to read, debug, and refactor complex existing codebases.

Preferred Qualifications

• Experience supporting high-throughput applications with a large active user base.
• Strong background in performance engineering and system optimization for enterprise-scale applications.