Senior Java Engineer

Acestack; Toronto; On-site; CAD 110,000 - 150,000; Full time

Job summary

Acestack is seeking a Senior Java Engineer to design, develop, and maintain robust Java applications on-site in Toronto, ON. You will implement clean code practices, build REST services, and collaborate with cross-functional teams to deliver high-quality software.

The role emphasizes strong Java fundamentals, experience with Spring Boot, and automated testing, with opportunities to apply AI-assisted development and automation tooling for quality and productivity.

Qualifications

• 5+ years of software development experience in Java and full life cycle.
• Strong command of core Java concepts including concurrency, streams, and memory management.
• Proven experience with unit testing (JUnit) and mocking (Mockito).

Responsibilities

• Design, develop, and maintain high-quality Java applications using clean code and design patterns.
• Write unit tests with JUnit/Mockito to ensure correctness and reliability.
• Apply TDD practices to drive design and coverage; continuously improve code quality through reviews and standards.
• Collaborate with architects and analysts to deliver secure, scalable REST services and microservices.

Skills

Java

Spring Boot

JUnit/Mockito

TDD

Clean code

Education

University Degree or College Diploma in Computer Science

Tools

Git

Maven

Gradle

Jenkins

SonarQube

JaCoCo

Docker

Kubernetes

AWS

Jira

Confluence

Job description

Senior Java Engineer

Location: Toronto, ON
Work Model: Onsite
Job Type: Full Time

Roles and Responsibilities

• Design, develop, and maintain high-quality, maintainable Java applications using clean code principles and established design patterns.
• Write comprehensive, meaningful unit tests using JUnit and Mockito to ensure code correctness, reliability, and long-term maintainability.
• Apply test-driven development (TDD) practices to drive design, maximize coverage, and prevent regressions.
• Champion code quality through thorough code reviews, pair programming, and adherence to coding standards and best practices.
• Refactor and improve existing codebases to reduce technical debt and enhance readability, performance, and testability.
• Apply core Java concepts-collections, concurrency and multithreading, generics, streams, exception handling, and JVM memory management-to build robust solutions.
• Integrate automated unit testing, static code analysis, and quality gates into CI/CD pipelines.
• Use tools such as SonarQube and JaCoCo to measure, enforce, and continuously improve code quality and test coverage.
• Build modular, reusable, and testable applications and APIs (REST web services) in Java.
• Collaborate with architects, business and application analysts, operations teams, and testing specialists to deliver reliable, secure, high-quality solutions.
• Diagnose, troubleshoot, and resolve complex technical, performance, and reliability issues.
• Ensure information security standards and requirements are incorporated into all solutions.
• Stay current with emerging technologies, including AI-assisted development and automated test generation, and evaluate how they can improve quality and productivity.

Skills Required

• 5+ years of software development experience in Java, spanning the full application development life cycle.
• Strong command of core Java concepts, including collections, concurrency/multithreading, generics, streams, lambdas, exception handling, and JVM memory management.
• Proven, hands-on experience writing effective unit tests with JUnit and mocking frameworks such as Mockito.
• Solid understanding of test-driven development (TDD), test automation, and continuous testing practices.
• Deep commitment to code quality, clean code, SOLID principles, and design patterns.
• Experience with static code analysis and code coverage tools such as SonarQube and JaCoCo.
• Experience building RESTful APIs and microservices using frameworks such as Spring / Spring Boot.
• Experience with build tools such as Maven or Gradle.
• Experience with source code management tools such as Git and Bitbucket.
• Experience integrating automated tests and quality checks into CI/CD pipelines, for example, Jenkins.
• Strong analytical, problem-solving, communication, and technical documentation skills.
• Ability to work effectively in a fast-paced, cross-functional Agile environment.

Nice to Have (Added Advantage)

• Experience using AI-assisted development tools, for example, GitHub Copilot, to accelerate coding and testing.
• Experience with AI-powered or automated unit test generation frameworks, for example, Diffblue Cover, EvoSuite, or similar, is a strong added advantage.
• Experience with integration, performance, and contract testing tools.
• Experience with containerization and orchestration technologies such as Docker and Kubernetes.
• Experience with cloud platforms such as AWS.
• Knowledge of security scanning tools such as SonarQube, JFrog Xray, or similar.
• Experience with Jira, Confluence, and Agile delivery practices.
• University Degree or College Diploma in Computer Science or a related technology field.
• Knowledge of the financial and insurance industries.

Primary Skills

Java, Spring Boot, JUnit/Mockito