Описание тега autowired
Autowiring is a DI container feature where the dependencies are automatically looked for according to some criteria.
In a ioc-container like spring-framework, the beans to be injected can be explicitely configured or they can be searched for automatically in what is called "autowiring".
Although the concept is not exclusive to Spring, the bulk of questions in stackru and Google seem to be directed towards this framework.
Spring
In the particular case of Spring, when " autowiring" is enabled, the container will look in the current ApplicationContext for a bean that matches the type/name of the corresponding setter method.
Autowiring can be configured globally or on each bean to be disabled; or enabled by type, by name, by constructor type. It can also be configured using the Autowired annotation.