Question

How I can do custom Java annotation with no attribute name inside parentheses?

I don’t want this: @annotation_name(att=valor). I just want like in Servlets, i.e:

@WebServlet("/main")

Answer 1

Define the annotation with an attribute named value, then the attribute name can be omitted:

@interface CustomAnnotation
{
    String value();
}

This can be used like so:

@CustomAnnotation("/main")
// ...

The special attribute name value is described in chapter "9.6.1. Annotation Interface Elements" of Java Language Specification:

By convention, the name of the sole element in a single-element annotation interface is value. Linguistic support for this convention is provided by single-element annotations (§9.7.3).