Java Developer

Patch Tech Staffing; Calgary; On-site; CAD 90,000 - 130,000; Full time

Job summary

Patch Tech Staffing is seeking a skilled Java Developer to design, develop, and maintain high-performance backend services. You will work on core Java components, build robust microservices with the Spring framework, and handle relational databases at scale.

You will collaborate with engineers, data teams, and architects in an Agile environment, focusing on performance, scalability, and clean code. Strong Java fundamentals and database expertise are essential for success.

Qualifications

• Proven expertise in core Java and multithreading.

Responsibilities

• Backend development: write clean, efficient core Java code for business functionality.
• Spring ecosystem: build and optimize enterprise apps using Spring (Boot, Data, etc.).
• Data & SQL optimization: design and tune complex queries, schemas, and indexes.
• Performance tuning: diagnose and optimize GC, memory, and concurrency.
• Collaborate with cross-functional teams in an Agile setting.

Skills

Core Java

Java Concurrency

JVM Tuning

Spring Framework

SQL & Data Modeling

Tools

Docker

Kubernetes

AWS/Azure/GCP

PostgreSQL

Oracle

MySQL

SQL Server

Kafka

RabbitMQ

Job description

We are seeking a skilled and proactive Java Developer to join our client’s engineering team. In this role, you will design, develop, and maintain high-performance backend systems and data services. You’ll be working with a collaborative team to tackle complex core Java components, build robust microservices using the Spring framework, and manage relational database operations at scale.

Responsibilities

• Backend Development: Write clean, efficient, and well-tested core Java code to support core business functionality.
• Spring Ecosystem: Build, scale, and optimize enterprise applications using the Spring Framework (Spring Boot, Spring Data, etc.).
• Data & SQL Optimization: Architect and fine-tune complex database queries, schema designs, joins, subqueries, and indexing strategies.
• Performance Tuning: Troubleshoot performance bottlenecks across the application tier and database level, including JVM garbage collection and concurrency optimization.
• Collaboration: Partner with cross-functional teams, software architects, and data engineers to implement backend solutions in an Agile environment.

Qualifications

Core Java & Backend Architecture

• Strong Core Java Expertise: Deep hands-on knowledge of core Java principles.
• Collections & Concurrency: Deep understanding of the Java Collections Framework, multithreading, concurrent data structures, and thread synchronization.
• JVM Fundamentals: solid understanding of JVM memory structure, basic Garbage Collection (GC) behavior, and memory/performance tuning.
• Spring Framework: Extensive real-world experience building enterprise applications with the Spring ecosystem (Spring Boot, MVC, Security, Dependency Injection).
• RDBMS Mastery: Strong experience working with enterprise Relational Databases (e.g., PostgreSQL, Oracle, MySQL, SQL Server).
• Advanced SQL: Proven ability to write and optimize complex SQL queries, multi-table joins, nested subqueries, and indexing strategies for peak performance.

Nice-to-Have Qualifications

• Experience with Snowflake (data warehouse concepts, writing queries, integrations) is a strong plus.
• Experience with CI/CD pipelines, Docker, Kubernetes, or cloud services (AWS/Azure/GCP).
• Familiarity with messaging queues (Kafka, RabbitMQ).