The Java programming language provided support for annotations from Java 5.0 onward. Leading Java frameworks were quick to adopt annotations, and the Spring Framework started using annotations from the 2.5 release. Due to the way they are defined, annotations provide a lot of context in their declaration.
Prior to annotations, the behavior of the Spring Framework was largely controlled through XML configuration. Today, the use of annotations provide us tremendous capabilities in how we configure the behaviors of the Spring Framework.