What is Spring framework?

Spring framework is mainly used for dependency management to establish dependencies between different objects in a project.
It uses inversion of control mechanism where you can configure the dependencies between objects in a configuration file.
Objects can be configured to be created with different scopes.
Spring framework takes care of creating objects and injects any dependencies (dependent objects) based on configuration.
It also provides integration support to other frameworks.
Spring has lot of flavours.
Spring Core, Spring AOP, Spring MVC, Springbatch, Spring Integration, Spring Security are some of them

Spring is light wieght container for varient commponents in WS, DB, transaction managment, security and others, also provide you with DI and AOP.