Java Developer Core Java & Multithreading: Operate

Job description

Java Developer - Core Java & Multithreading: Operate



**Date:** Mar 15, 2026



**Location:** Toronto, ON, CA, M5C 3G7



**Company:** Deloitte



**Job Type:** Temporary Contract

**Work Model:** Hybrid

**Reference code:** 132690

**Primary Location:** Toronto, ON

**All Available Locations:** Toronto, ON



**Our Purpose**



At Deloitte, our Purpose is to make an impact that matters.

We exist to inspire and help our people, organizations, communities, and countries to thrive by building a better future.

Our work underpins a prosperous society where people can find meaning and opportunity.

It builds consumer and business confidence, empowers organizations to find imaginative ways of deploying capital, enables fair, trusted, and functioning social and economic institutions, and allows our friends, families, and communities to enjoy the quality of life that comes with a sustainable future.

And as the largest 100% Canadian-owned and operated professional services firm in our country, we are proud to work alongside our clients to make a positive impact for all Canadians.



By living our Purpose, we will make an impact that matters.



+ Have many careers in one Firm.

+ Enjoy flexible, proactive, and practical benefits that foster a culture of well-being and connectedness.

+ Learn from deep subject matter experts through mentoring and on the job coaching



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We are seeking a Java Developer to join our team on a **1-year fixed term** .

In this role you will design, build, and optimize high-performance, resilient services and applications using Core Java with a strong emphasis on concurrency and multithreading.

You’ll collaborate with cross-functional teams to deliver scalable solutions, improve system throughput and latency, and enforce engineering best practices across the SDLC.

If you enjoy solving complex problems at scale and care deeply about clean, reliable code, this role is for you.



**What will your typical day look like?**



+ Design & Development: Build robust backend services and APIs using Core Java (8/11/17+), applying multithreading and concurrency control (e.g., java.util.concurrent, locks, atomics, thread pools) to deliver low-latency, high-throughput systems.

+ Performance & Reliability: Diagnose and resolve bottlenecks using profilers (e.g., JFR, VisualVM), optimize GC behavior, tune thread pools, and enhance system resiliency (timeouts, retries, circuit breakers).

+ Architecture & Code Quality: Contribute to technical design, write clean, testable code, and participate in code reviews to uphold standards (SOLID, effective immutability, defensive programming).

+ Microservices & Integration: Develop and maintain microservices (Spring Boot), integrate with RESTful APIs, messaging (Kafka/RabbitMQ), and data stores (SQL/NoSQL).

+ Testing & Automation: Implement unit, integration, and load tests (JUnit, Mockito, Testcontainers, Gatling/JMeter).

Contribute to CI/CD pipelines and DevOps automation.

+ Observability: Instrument services with logging, metrics, and tracing (ELK/EFK, Prometheus/Grafana, OpenTelemetry) to support proactive monitoring and incident resolution.

+ Collaboration: Work with product owners, architects, and QA to refine requirements, break down work, and deliver iteratively in an Agile environment (Scrum/Kanban).

+ Security & Compliance: Apply secure coding practices (OWASP Top 10), handle secrets responsibly, and contribute to threat modelling and secure design reviews.

+ Documentation: Produce clear technical documentation, runbooks, and knowledge articles to enable maintainability and operational excellence.



**About the team**



This is your opportunity to work in Operate at Deloitte.

Operate services harness the latest technologies, talent, and capabilities from all over the world to deliver ongoing outcomes and client value.

We do more than traditional business process outsourcing.

We do more than just “keeping the lights on.” We work shoulder-to-shoulder with clients and their customers, constantly adapting to the pace of change, to ideate, innovate, and embed continuous advantage at the heart of their operations.

And we do it with the kind of drive and passion that comes from loving what you do—and who you do it with.



**Enough about us, let’s talk about you**



You are someone with these skills, experience & qualifications:



+ 6+ years of professional experience in Core Java development (Java 8/11/17+), with deep knowledge of:

+ Concurrency & Multithreading: thread safety, synchronization, locks, atomics, CompletableFuture, fork/join, thread pools, non-blocking patterns.

+ JVM Internals: memory model, GC tuning, heap/stack, classloading basics.

+ Collections & Generics: performance trade-offs, immutability, defensively copying.

+ Hands-on with Spring Boot, RESTful APIs, and microservice patterns.

+ Experience with relational databases (e.g., PostgreSQL/Oracle/MySQL) and at least one NoSQL store (e.g., Redis/MongoDB); strong SQL skills and query optimization.

+ Proficiency in unit/integration testing (JUnit/Mockito/Testcontainers) and build tools (Maven/Gradle).

+ Working knowledge of CI/CD (GitHub Actions/Azure DevOps/Jenkins), containers (Docker), and exposure to Kubernetes.

+ Experience with performance profiling and observability (metrics, logs, traces).

+ Solid understanding of design patterns, SOLID principles, and clean code practices.

+ Strong communication skills and a collaborative mindset in Agile teams.



**Total Rewards**



The salary range for this position is $72,000 - $138,000, and individuals may be eligible to participate in our bonus program.

Deloitte is fair and competitive when it comes to the salaries of our people.

We regularly benchmark across a variety of positions, industries, sectors, targets, and levels.

Our approach is grounded on recognizing people's unique strengths and contributions and rewarding the value that they deliver.



Our Total Rewards Package extends well beyond traditional compensation and benefit programs and is designed to recognize employee contributions, encourage personal wellness, and support firm growth.

Along with a competitive base salary and variable pay opportunities, we offer a wide array of initiatives that differentiate us as a people-first organization.

On top of our regular paid vacation days, some examples include: $4,000 per year for mental health support benefits, a $1,300 flexible benefit spending account, firm-wide closures known as Deloitte Days, dedicated days of for learning (known as Development and Innovation Days), flexible work arrangements and a hybrid work structure.



**Our promise to our people: Deloitte is where potential comes to life.**



**Be yourself, and more.**



We are a group of talented people who want to learn, gain experience, and develop skills.

Wherever you are in your career, we want you to advance.



**You shape how we make impact.**



Diverse perspectives and life experiences make us better.

Whoever you are and wherever you’re from, we want you to feel like you belong here.

We provide flexible working options to support you and how you can contribute.



**Be the leader you want to be**



Some guide teams, some change culture, some build essential expertise.

We offer opportunities and experiences that support your continuing growth as a leader.



**Have as many careers as you want.**



We are uniquely able to offer you new challenges and roles – and prepare you for them.

We bring together people with unique experiences and talents, and we are the place to develop a lasting network of friends, peers, and mentors.



**The next step is yours**



At Deloitte, we are all about doing business inclusively – that starts with having diverse colleagues of all abilities.

Deloitte encourages applications from all qualified candidates who represent the full diversity of communities across Canada.

This includes, but is not limited to, people with disabilities, candidates from Indigenous communities, and candidates from the Black community in support of living our values, creating a culture of Diversity Equity and Inclusion and our commitment to ourAccessAbility Action Plan (https://www2.deloitte.com/ca/en/pages/public-sector/articles/accessability-action-plan.html) , Reconciliation Action Plan (https://www.deloitte.com/ca/en/about/story/purpose-values/reconciliation-action-plan.html) and the BlackNorth Initiative (https://www2.deloitte.com/ca/en/pages/about-deloitte/articles/black-in-canada-acknowledging-our-past.html) .



We encourage you to connect with us at accessiblecareers@deloitte.ca if you require an accommodation for the recruitment process (including alternate formats of materials, accessible meeting rooms or other accommodations) or indigenouscareers@deloitte.ca for any questions relating to careers for Indigenous peoples at Deloitte (First Nations, Inuit, Métis).



When you apply, we will review your application using Deloitte's Global Talent Standards to ensure a consistent recruitment experience.

Our recruitment advisors and hiring teams will utilize human screening combined with AI technology to help identify the skills and qualities that matter most to our business, while safeguarding your privacy and using AI responsibly.



Deloitte Canada has 20 offices with representation across most of the country.

We acknowledge that Deloitte offices stand on traditional, treaty, and unceded territories in what is now known as Canada.

We recognize that Indigenous Peoples have been the caretakers of this land since time immemorial, nurturing its resources and preserving its natural beauty.

We acknowledge this land is still home to many First Nations, Inuit, and Métis Peoples, who continue to maintain their deep connection to the land and its sacred teachings.

We humbly acknowledge that we are all Treaty people, and we commit to fostering a relationship of respect, collaboration, and stewardship with Indigenous communities in our shared goal of reconciliation and environmental sustainability.

Required Skill Profession

Other General