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Contract Senior Java Developer Jobs in Ontario (NOW HIRING)

SENIOR JAVA SOFTWARE DEVELOPER Location: Toronto, ON (uptown) Industry: Technology Type: Permanent WHAT IS THE OPPORTUNITY. Our client is an 18-year-old SaaS developer and recognized leader of ...

\n \n \n \n \n Our client in Galway are beginning to hire Java Engineers (up to senior level) to help the team build out their globally renowned and ever\-present SAAS offering on a permanent basis.

\n \n \n \n \n We are looking for an experienced Java Developer for a contract position in Dublin. You will be joining a rapidly expanding team who are working on the most cutting edge products. \n \n ...

\n \n \n \n \n We are looking for an experienced Java Developer for a contract position in Dublin. You will be working as part of an agile team to deliver the highest quality solutions! \n \n \n \n \n ...

\n \n \n \n \n We have a contract position available for a Java developer within a rapidly growing global team. You will be responsible for the design and development of the company's platform and ...

Senior Java Developer

Etobicoke, ON · Hybrid

CA$120K - CA$140K/yr

As a Senior Java Back-End Developer at Localcoin, you will be responsible for developing and maintaining functional and stable back end applications for our company, ensuring system consistency and ...

\n \n \n \n \n Are you a Senior Java Developer with extensive cloud experience looking for your next challenge? Do you have Microservices and TDD? Are you interesting in working in the banking sector?

Senior Java Developer

Mississauga, ON · On-site

CA$94K - CA$141K/yr

We are seeking a highly motivated and experienced Senior Java Developer to join our dynamic team focused on enhancing developer productivity. Our mission is to build and maintain cutting-edge ...

\n \n \n \n Senior Java Engineer \- \/AWS \n \n \n \n \n \n ... Dublin\/ Galway - Remote\/WFH\n \n * Long Term Contract\n \n * Negotiable Day Rate\n \n \n \n \n \n ...

We are seeking a highly motivated and experienced Senior Java Developer to join our dynamic team focused on enhancing developer productivity. Our mission is to build and maintain cutting-edge ...

The Applications Development Senior Manager (Senior Java Developer - Vice President) is a senior-level position responsible for driving results through hands-on technical leadership and team guidance ...

A Java Developer designs, develops, tests, and maintains scalable Java-based applications (web, enterprise, mobile) by writing clean code, collaborating with teams, and integrating with databases and ...

Senior Java Developer

Mississauga, ON · On-site

CA$94K - CA$141K/yr

The Senior Java Developer is an intermediate level position responsible for participation in the establishment and implementation of new or revised application systems and programs in coordination ...

Senior Java Developer

Mississauga, ON · On-site

CA$94K - CA$141K/yr

We are seeking a highly experienced and motivated Lead Java Developer with 6+ years of industry experience to spearhead the development of robust, scalable, and innovative enterprise applications.

Senior Java Developer

Toronto, ON · Hybrid

CA$120K - CA$145K/yr

About The Role As a Full Stack Java Developer you'll be tasked with working on web application development in Java and Spring Boot. Working within the software development team, your duties will ...

... on a Senior Software Engineer vacancy (multiple available). \n \n \n \n \n \n \n We need someone ... Highly skilled Software Engineer, ideally 7+ years' experience primarily in Java (flexible)\n \n

Senior Java Developer

Mississauga, ON · On-site +1

CA$129K - CA$194K/yr

Primary Programming Languages: Java, Bash shell and Coreutils, Perl, Python, Go, Rust * OS/Technologies: Linux SuSE Operating system * Experience in DICOM and HL7 * An undergraduate or college degree ...

Showing results 21-40

Contract Senior Java Developer information

What is a contract senior Java developer?

A Contract Senior Java Developer is an experienced software engineer who specializes in Java programming and works on a contract basis rather than as a permanent employee. They are typically responsible for designing, developing, and maintaining complex Java applications, often leading technical teams and ensuring code quality. Their contract status means they are hired for specific projects or time frames, providing flexibility to both the developer and the employer. Senior Java Developers usually have several years of experience and a deep understanding of Java frameworks, best practices, and software architecture.

What are some common challenges faced by contract senior Java developers when joining new projects?

Contract Senior Java Developers often encounter challenges such as quickly adapting to unfamiliar codebases, integrating with established development teams, and understanding unique business requirements. Since contracts are typically time-limited, there is pressure to deliver results efficiently while maintaining high code quality. Building rapport with permanent staff and navigating different development processes or toolchains are also common hurdles, but strong communication skills and adaptability can help overcome these challenges.

What are the key skills and qualifications needed to thrive as a contract senior Java developer, and why are they important?

To thrive as a Contract Senior Java Developer, you need advanced proficiency in Java programming, object-oriented design, and experience with frameworks like Spring or Hibernate, typically backed by a bachelor's degree in computer science or related field. Familiarity with version control systems (such as Git), CI/CD pipelines, and cloud platforms like AWS or Azure is often required, along with relevant Java certifications. Strong problem-solving, communication, and time management skills help you effectively collaborate with distributed teams and deliver quality code on tight deadlines. These skills and qualities are crucial for building robust applications, adapting to evolving project requirements, and excelling in fast-paced contract environments.

What is the difference between Contract Senior Java Developer vs Contract Java Developer?

AspectContract Senior Java DeveloperContract Java Developer
Required CredentialsJava certifications, experience in complex projectsJava certifications, basic to intermediate experience
Work EnvironmentLarge enterprise, complex systemsStartups, small to medium projects
Employer & Industry UsageFinancial, healthcare, tech firmsTech startups, software agencies
Search & Comparison IntentSeeking experienced Java roles, seniority levelEntry to mid-level Java roles

The main difference between a Contract Senior Java Developer and a Contract Java Developer lies in experience, project complexity, and industry usage. Senior developers typically handle complex systems and require advanced certifications, while Java Developers may work on simpler projects with less experience. Both roles are in demand across various industries, but the senior position emphasizes leadership and technical expertise.

What are the most commonly searched types of Senior Java Developer jobs in Ontario?

The most popular types of Senior Java Developer jobs in Ontario are:

What are popular job titles related to Contract Senior Java Developer jobs in Ontario?

For Contract Senior Java Developer jobs in Ontario, the most frequently searched job titles are:

What job categories do people searching Contract Senior Java Developer jobs in Ontario look for?

The top searched job categories for Contract Senior Java Developer jobs in Ontario are:

What cities in Ontario are hiring for Contract Senior Java Developer jobs?

Cities in Ontario with the most Contract Senior Java Developer job openings:

Infographic showing various Contract Senior Java Developer job openings in Ontario as of September 2026, with employment types broken down into 93% Full Time, and 7% Contract. Highlights an 52% In-person, 31% Hybrid, and 17% Remote job distribution.

Senior Java developer

Ottawa, ON • On-site

Full-time

Posted 27 days ago


Job description

We are seeking a senior Java developer to join our team in a full-time employment capacity. This role requires expertise in Java-based systems, along with experience in audio codec integration, VOIP/ROIP protocols, and mission-critical communication systems. The successful candidate will play a key role in the development and enhancement of applications that support military and emergency services communication platforms, ensuring reliability, security, and performance under demanding conditions.
 
Key Responsibilities:
  • Design, develop, and maintain Java applications for use with VOIP/ROIP and digital communication systems.
  • Integrate and optimize audio codecs (e.g., Opus, AAC Audio).
  • Work on SIP, RTP, and other VOIP/ROIP protocols for real-time communication.
  • Collaborate with cross-functional teams to design secure and fault-tolerant communication solutions.
  • Develop and implement features for interoperability with military communication systems.
  • Ensure scalability, low-latency performance, and high availability of communication services.
  • Participate in code reviews, architecture discussions, and technical planning.
  • Regular customer engagement for the purposes of requirements gathering, feature demonstrations, and product support.
Required Qualifications
  • Bachelor’s degree in computer science, Engineering, or a related field.
  • 10+ years of experience in Java development.
  • Located in the Ottawa area or willing to relocate to the Ottawa area.
  • Experience developing distributed client/server environments.
  • In-depth knowledge of VOIP/ROIP technologies (e.g., SIP, RTP, SRTP).
  • Hands-on experience with audio codecs and real-time media processing.
  • Familiarity with radio systems, digital signal processing (DSP), and tactical communication protocols.
  • Strong understanding of network programming and low-level socket communication.
  • Excellent problem-solving, debugging, and performance optimization skills.
 
Preferred Qualifications
  • Experience developing communication software for military, defence, or emergency services.
  • Familiarity with Open SDR (software-defined radio).
  • Active security clearance (Secret or higher).