Java Developer

HackerKernel; India; Hybrid; INR 1,200,000 - 2,100,000; Full time

Job summary

HackerKernel in India is seeking an experienced Java Developer to build backend services and REST APIs using Core Java and Spring Boot. You will work on database-driven, scalable software solutions and collaborate across QA, product, and frontend teams to deliver high-quality applications.

The role requires 3+ years of hands-on Java experience, strong OOP and multithreading skills, and solid SQL knowledge with MySQL or PostgreSQL. Hybrid/remote work options available based on project needs.

Qualifications

• 3+ years of professional experience in Java development.
• Strong hands-on knowledge of Core Java.
• Strong understanding of OOP, Collections, Multithreading, Streams and Lambda Expressions, Design Patterns.
• Strong experience with Spring Boot and Spring Data JPA / Hibernate.
• Strong SQL knowledge with MySQL/PostgreSQL or similar databases.
• Experience with Git/GitHub.
• Good debugging and problem-solving skills.
• Understanding of software development lifecycle and coding best practices.
• Good communication and teamwork skills.

Responsibilities

• Develop, maintain, and enhance Java-based applications and backend services.
• Write clean, scalable, reusable, and maintainable code using Core Java.
• Develop and integrate RESTful APIs.
• Work with Spring Boot, Spring MVC, Spring Data JPA/Hibernate.
• Design and work with relational databases such as MySQL/PostgreSQL.
• Write optimized SQL queries and handle database integration.
• Debug, troubleshoot, and resolve application issues.
• Participate in code reviews and follow coding standards and best practices.
• Collaborate with frontend developers, QA engineers, product teams, and other stakeholders.

Skills

Core Java

OOP

Multithreading

Spring Boot

Spring Data JPA

Hibernate

SQL

Git

Problem solving

Communication

Tools

MySQL

PostgreSQL

Kafka

RabbitMQ

Redis

Docker

Maven

Gradle

Jenkins

Swagger/OpenAPI

Job description

Job Description

We are looking for an experienced Java Developer with 3+ years of hands-on experience in Java development. The ideal candidate should have strong knowledge of Core Java and practical experience in developing backend applications, REST APIs, database-driven applications, and scalable software solutions.

You will be responsible for developing, maintaining, debugging, and optimizing Java-based applications while working closely with developers, QA, product teams, and other stakeholders.

Key Responsibilities

• Develop, maintain, and enhance Java-based applications and backend services.
• Write clean, scalable, reusable, and maintainable code using Core Java.
• Apply strong understanding of OOP concepts, Collections, Exception Handling, Multithreading, and Java 8+ features
• Develop and integrate RESTful APIs.
• Work with **Spring Boot, Spring MVC, Spring Data JPA/Hibernate.
• Design and work with relational databases such as MySQL/PostgreSQL.
• Write optimized SQL queries and handle database integration.
• Debug, troubleshoot, and resolve application issues.
• Participate in code reviews and follow coding standards and best practices.
• Work with Git/GitHub for version control.
• Write unit and integration tests and ensure application quality.
• Collaborate with frontend developers, QA engineers, product teams, and other stakeholders.
• Understand business requirements and convert them into technical solutions.
• Optimize application performance, reliability, and scalability.
• Contribute to existing projects as well as new feature development.

Required Skills

• 3+ years of professional experience in Java development.
• Strong hands‑on knowledge of Core Java.
• Strong understanding of:
• OOPs
• Collections
• Multithreading
• Streams and Lambda Expressions
• Design Patterns
• Good experience with Spring Boot.
• Good knowledge of Spring Data JPA / Hibernate.
• Strong SQL knowledge with MySQL/PostgreSQL or similar databases.
• Experience with Git/GitHub.
• Good debugging and problem‑solving skills.
• Understanding of software development lifecycle and coding best practices.
• Good communication and teamwork skills.

Good to Have

• Experience with Microservices architecture.
• Knowledge of Spring Security / JWT / OAuth2.
• Experience with Kafka, RabbitMQ or Redis.
• Knowledge of Docker.
• Exposure to AWS, Azure or other cloud platforms.
• Experience with JUnit / Mockito.
• Knowledge of Maven or Gradle.
• Familiarity with CI/CD tools such as Jenkins or GitHub Actions.
• Experience with Swagger/OpenAPI.
• Basic understanding of Linux and deployment processes.

Requirements

• 3+ years of professional experience in Java development.
• Strong hands‑on knowledge of Core Java.
• Strong understanding of:
• OOPs
• Collections
• Multithreading
• Streams and Lambda Expressions
• Design Patterns
• Good experience with Spring Boot.
• Good knowledge of Spring Data JPA / Hibernate.
• Strong SQL knowledge with MySQL/PostgreSQL or similar databases.
• Experience with Git/GitHub.
• Good debugging and problem‑solving skills.
• Understanding of software development lifecycle and coding best practices.
• Good communication and teamwork skills.
• Work on live and international projects.
• Opportunity to work with modern technologies and development practices.
• Collaborative and learning‑focused work environment.
• Hybrid / remote work opportunities based on project requirements.
• Opportunity to grow with a fast‑growing technology company.