Spring is a framework to develop enterprise applications with Java. It provides features like dependency injection, simplified database access, and system integration via REST APIs or messaging. The Spring Boot project simplifies working with Spring by providing features like automatic configuration and dependency management for commonly used libraries.

Further information: https://en.wikipedia.org/wiki/Spring_Framework

Documentation

• Spring Tutorial
• Spring Guides
• Spring Framework Documentation

Advantages

• Spring makes 90% of the development tasks very easy.
• Spring Boot works with the idea of convention over configuration. This means that complex functionality can be achieve with a very little amount of code.

Disadvantages

• Spring makes 10% of the development tasks very difficult.
• Spring Boot works with the idea of convention over configuration. This means that a lot of hidden things are happening which are hard to understand without being familiar with the underlying mechanisms and the documentation of those features.