Spring Framework is a web application and application framework for Java and the JVM.
Spring is designed to help you build applications by wiring components together through dependency injection and configuration.
The main pieces people usually mean when they say “Spring” are:
- Spring Core, which provides dependency injection and the application context
- Spring MVC, which handles web requests and responses
- Spring Boot, which simplifies application setup and packaging
- Spring Data, which helps with database access and repositories
- Spring Security, which handles authentication and authorization
Spring is often used with:
- REST APIs
- Database-backed enterprise applications
- Microservices
- Message brokers such as Kafka or RabbitMQ
Why people use it
Spring is a common choice for large Java systems because it gives strong structure, a large ecosystem, and flexible integration points.
It is especially strong for:
- Enterprise applications
- APIs and backend services
- Applications that need dependency injection and modular configuration
- Systems that need lots of integration with other Java libraries
Tradeoffs
Spring can feel more complex than smaller frameworks, especially if you only need a small service. The payoff is that it scales well for larger systems with many moving parts.
Rule of thumb:
- Use Spring when you want a mature JVM framework with a large ecosystem
- Use a lighter framework when you only need a small Java service or minimal API