Question

I found a strange annotation:

public static @interface WebResult { }

Why is static there? How do they compile it? My IDE does not allow such modifier there!

The class this is contained in is javax.jws.WebResult.

Answer 1

It’s valid (but not required) when it’s nested inside another class:

public class Foo {   
    public static @interface Bar {
    }    
}

From the Java language specification section 8.5.2:

Member interfaces are always implicitly static. It is permitted but not required for the declaration of a member interface to explicitly list the static modifier.

If you’ve seen it on a top-level class, please show where you’ve found it like that.