The basic concept of the Inversion of Control pattern (dependency injection) is that programmers don’t need to create your objects but describe how they should be created. Don’t directly connect your components and services together in code but describe which services are needed by which components in a configuration file. A container (in the case of the Spring framework, the IOC container) is responsible for all this. In a IOC scenario, the container creates all the objects, connects them together by setting the necessary properties, and determines when methods will be invoked. The implementation pattern types for IOC used by SpringFramework are as follows:
- Dependencies can be assigned through JavaBeans properties (setter methods).
- Dependencies are provided as constructor parameters and are not exposed as JavaBeans Setter properties.