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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Sr. Core Java Developer / Lead - **Company:** Congensys Corp - **Location:** Menlo Park, CA, United States - **Experience:** Expert - **Contract:** Permanent contract - **Skills:** Clean Code Principles, Java (Programming Language), Spring Security, Apache ActiveMQ, Amazon Web Services, Component-Based Software Engineering, Business Logic, Microsoft Azure, Profiling, Code Review, Databases, Continuous Integration, Serialization, Data Structures, Database Development, Software Debugging, Software Design Patterns, Linux, DevOps, Distributed Systems, Memory Management, Amazon DynamoDB, Github, Gradle, HP Systems Insight Manager, Java Platform Standard Edition (J2SE), Java Database Connectivity, Java Message Service (JMS), Java Virtual Machine (JVM), Junit, Apache Maven, MongoDB, NoSQL, Object-Oriented Software Development, Scrum Methodology, RabbitMQ, Redis, Mockito, Oop Languages, Standard Sql, Memory Leaks, Secure Coding, Shell Script, Software Deployment, Software Engineering, SQL Databases, Multithreading, Google Cloud, Enterprise Software Applications, Performance Testing, Spring-mvc, Grafana, Concurrency, Spring-boot, Software Security, Caching, Backend, Git, Spring Data, Event Driven Architecture, Gitlab-ci, Integration Tests, Information Technology, Cassandra, Apache Kafka, Restful APIs, Docker, Jenkins, Microservices - **Published:** August 14, 2026 - **Apply:** https://www.dice.com/job-detail/037ff78d-c78f-49a3-baf3-8d82037cb5b1 ## About the Role We are seeking a highly skilled Sr. Core Java Developer / Lead with 10+ years of experience in Java software development to design, develop, test, and maintain high-performance, scalable, and reliable enterprise applications. The ideal candidate will have strong expertise in Core Java, OOP, multithreading, concurrency, data structures, design patterns, JVM, memory management, REST APIs, and enterprise backend development., * 10+ years of professional Java development experience. * Strong hands-on experience with Core Java / Java SE. * Strong knowledge of: + Object-Oriented Programming + Collections Framework + Generics + Exception Handling + Multithreading & Concurrency + Java I/O & NIO + Streams & Lambda Expressions + JVM Architecture + Memory Management & Garbage Collection + Serialization & Reflection * Strong Data Structures and Algorithms knowledge. * Experience with Java 8 or later. * Experience developing RESTful APIs and backend services. * Strong SQL and database development experience. * Experience with JDBC and ORM concepts. * Experience with Spring / Spring Boot. * Experience with Maven or Gradle. * Experience with Git. * Experience with JUnit / Mockito. * Strong debugging and problem-solving skills. * Experience working in Agile/Scrum environments. Preferred Skills * Java 11, 17, 21 or later. * Spring MVC, Spring Data, Spring Security. * Microservices architecture. * Kafka, RabbitMQ, JMS, or ActiveMQ. * Docker and Kubernetes. * AWS, Azure, or Google Cloud. * MongoDB, Redis, Cassandra, or DynamoDB. * Distributed systems and event-driven architecture. * Caching technologies. * CI/CD tools such as Jenkins, GitHub Actions, GitLab CI, or Azure DevOps. * Application monitoring and observability tools. * Performance testing and profiling. * Linux/Unix and shell scripting. * Secure coding and application security practices., Bachelor's degree in Computer Science, Engineering, Information Technology, or a related field preferred., Candidates should have strong hands-on Core Java development experience and be available to work from the specified location. ## Description * Design, develop, test, and maintain applications using Core Java. * Write clean, efficient, reusable, and maintainable code. * Apply OOP principles, design patterns, and best coding practices. * Develop multithreaded and highly concurrent applications. * Work with Java Collections, Generics, Streams, Lambda expressions, and exception handling. * Develop and consume RESTful APIs and backend services. * Build modular, scalable, and high-performance application components. * Implement business logic, validation, error handling, and transaction management. * Work with relational and NoSQL databases. * Write and optimize SQL queries and database interactions. * Troubleshoot production issues, memory leaks, performance bottlenecks, and application defects. * Participate in code reviews and technical design discussions. * Develop unit and integration tests using JUnit, Mockito, or equivalent tools. * Integrate applications with CI/CD pipelines. * Collaborate with architects, developers, QA, DevOps, product managers, and business stakeholders. * Participate in Agile/Scrum ceremonies and sprint activities. * Support application deployment, monitoring, and production issue resolution. ## Related Videos - [Enterprise-Cloud-Native - Fast-Paced Development & Deployment in a Highly Secure Banking Environment](https://www.wearedevelopers.com/videos/671-enterprise-cloud-native-fast-paced-development-deployment-in-a-highly-secure-banking-environment) - [How a Small Team Shrank a Microsoft Monorepo by 94%](https://www.wearedevelopers.com/videos/1236-how-a-small-team-shrank-a-microsoft-monorepo-by-94) - [Docker network without Docker](https://www.wearedevelopers.com/videos/1418-docker-network-without-docker) - [Reducing LLM Calls with Vector Search Patterns - Raphael De Lio (Redis)](https://www.wearedevelopers.com/videos/1714-reducing-llm-calls-with-vector-search-patterns-raphael-de-lio-redis) - [The Open-source Java SDK for Multi-Cloud Development - Sandeep Pal](https://www.wearedevelopers.com/videos/2113-the-open-source-java-sdk-for-multi-cloud-development-sandeep-pal) - [Git for Code Reviews](https://www.wearedevelopers.com/videos/429-git-for-code-reviews) ## Related Articles - [How We Built a Worry-Free System That Runs for 10+ Years – And What We’d Do Again](https://www.wearedevelopers.com/magazine/751-how-we-built-a-worry-free-system-that-runs-for-10-years-and-what-we-d-do-again) - [Why Attend a Developer Event in 2026?](https://www.wearedevelopers.com/magazine/688-why-attend-a-developer-event-in-2026) - [Is Software Engineering Over-Saturated?](https://www.wearedevelopers.com/magazine/418-is-software-engineering-over-saturated) - [What’s the Difference between a Junior, Mid, and Senior Developer?](https://www.wearedevelopers.com/magazine/238-what-s-the-difference-between-a-junior-mid-and-senior-developer) - [93 Java Interview Questions You Should Prepare For](https://www.wearedevelopers.com/magazine/14-93-java-interview-questions-you-should-prepare-for) - [Top 10 Java Libraries](https://www.wearedevelopers.com/magazine/364-top-10-java-libraries)