What alternatives to Spring do you know?

Alternatives to Spring in the Java ecosystem:

• Jakarta EE (formerly Java EE) — a standard platform for enterprise applications with support for DI, transactions, JPA, etc.
• Micronaut — a modern framework with fast startup and low memory consumption, focused on microservices.
• Quarkus — optimized for containers and the cloud, supports reactive programming.
• Dropwizard — a minimalist framework for creating RESTful services.
• Google Guice — a dependency injection library, lighter than Spring.

The choice depends on project requirements: scale, performance, ecosystem, and team preferences.