Sr. Core Java Developer / Lead

Congensys Corp; Alpharetta (GA); On-site; USD 130,000 - 180,000; Full time

Job summary

Congensys Corp seeks a Senior Core Java Developer/Lead to design, develop, test, and maintain high-performance enterprise Java applications. The candidate will apply expertise in Core Java, OOP, multithreading, REST APIs, Spring Boot, databases, and modern enterprise development practices.

The ideal candidate will have 10+ years of experience, deep knowledge of Java 8+ features, and hands-on experience with microservices, CI/CD, and agile methodologies.

Qualifications

• 10+ years of Java software development experience.
• Strong expertise in Core Java / Java SE.
• Proficient in Object-Oriented Programming and Design Patterns.
• Experience with multithreading and concurrency.
• Hands-on with RESTful APIs and backend services.
• Proficient in Spring, Spring MVC, Spring Boot.
• Strong SQL knowledge and relational databases.
• Experience with build tools (Maven/Gradle) and version control (Git).

Responsibilities

• Design, develop, and maintain scalable Java applications.
• Build multithreaded, high-performance software components.
• Develop and consume RESTful APIs.
• Collaborate with teams across the stack and QA.
• Contribute to architectural decisions and code reviews.
• Support deployment, monitoring, and production issue resolution.

Skills

10+ years Java experience

Core Java / Java SE

OOP & design patterns

Multithreading & concurrency

REST APIs

Spring / Spring Boot

Databases & SQL

Maven/Gradle

Git

JUnit/Mockito

Agile/Scrum

Debugging & problem-solving

Tools

Maven/Gradle

Git

JUnit

Job description

Location: Alpharetta, GA / Menlo Park, CA

Local Candidates Only

W2 Only - No C2C/1099

Job Description

We are seeking a highly skilled Senior Core Java Developer / Lead to design, develop, test, and maintain high-performance, scalable, and reliable enterprise Java applications.

The ideal candidate will have strong expertise in Core Java, object-oriented programming, multithreading, data structures, design patterns, REST APIs, Spring Boot, databases, and enterprise application development.

Required Skills

• 10+ years of experience in Java software development
• Strong expertise in Core Java / Java SE
• Object-Oriented Programming and Design Patterns
• Collections Framework, Generics, Exception Handling
• Multithreading and Concurrency
• Java I/O and NIO
• Streams and Lambda Expressions
• JVM Architecture, Memory Management, and Garbage Collection
• Data Structures and Algorithms
• Java 8 or later
• RESTful APIs and backend services
• Spring, Spring MVC, and Spring Boot
• Microservices architecture
• Relational databases such as Oracle, SQL Server, MySQL, or PostgreSQL
• SQL, JDBC, and ORM concepts
• Maven or Gradle
• Git or other version-control systems
• Unit testing with JUnit, Mockito, or equivalent
• Agile/Scrum methodology
• Strong debugging, analytical, communication, and problem-solving skills

Preferred Skills

• Java 11, 17, 21 or later
• Kafka, RabbitMQ, JMS, or ActiveMQ
• Docker and Kubernetes
• AWS, Azure, or Google Cloud
• Jenkins, GitHub Actions, GitLab CI, or Azure DevOps
• MongoDB, Redis, Cassandra, or DynamoDB
• Distributed systems and event-driven architecture
• Caching and high-performance application development
• Application monitoring and observability tools
• Secure coding and application security
• Performance testing and profiling
• Linux/Unix and shell scripting

Key Responsibilities

• Design, develop, and maintain scalable applications using Core Java
• Develop multithreaded and high-performance applications
• Build and consume RESTful APIs
• Develop modular and reusable backend components
• Work with relational and NoSQL databases
• Write efficient SQL queries and optimize database interactions
• Perform unit, integration, functional, and regression testing
• Troubleshoot production issues, memory leaks, and performance bottlenecks
• Participate in code reviews and technical design discussions
• Contribute to HLD/LLD and implementation plans
• Integrate applications with CI/CD pipelines
• Support application deployment, monitoring, and production issue resolution
• Collaborate with architects, developers, QA, DevOps, product managers, and business stakeholders
• Participate in Agile ceremonies and sprint activities
• Provide technical leadership and guidance to development teams