Creating Custom Annotations and Making Use of Them

How to Create a Custom Annotations?Read full article from 

public @interface Copyright {
   String info() default "";
}

Since we didn't define any @Target , you can use this annotation anywhere in your classes by default. If you want your annotation to be only available for class-wise or method-wise, you should define @Target annotation. 
annotations are interfaces, so you don't implement anything in them.
How to Make Use of Your Custom Annotations?

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface Test {
   Class expected();
}

@Retention marks our annotation to be retained by JVM at runtime. This will allow us to use Java reflections later on.

Test test = method.getAnnotation(Test.class);
// we use Class type here because our attribute type
// is class. If it would be string, you'd use string
Class expected = test.expected();
try {
   method.invoke(null);
   pass++;
} catch (Exception e) {
   if (Exception.class != expected) {
       fail++;
   } else {
       pass++;
   }
}

Creating Custom Annotations and Making Use of Them