How do annotations like @Override work internally in Java?

Question

Can anybody explain to me how annotations work internally in java?

I know how we can create custom annotations by using java.lang.annotation library in java. But I s

Answer 1

Basically, annotations are just markers which are read by the compiler or the application. Depending on their retention policy they are available at compile time only or are readable at runtime using reflection.

Many frameworks use runtime retention, i.e. they reflectively check whether some annotations are present on a class, method, field etc. and do something if the annotation is present (or not). Additionally, members of annotations can be used to pass further information.