Question

We can use getAnnotations() on an interface of Annotation but not getAnnotation? Why
When I changed the interface from MyAnno to Annotation in the followng program, the compiler was not recognizing the data defined in the Annotation like the str() etc…

package british_by_blood;

import java.lang.annotation.*;
import java.lang.reflect.*;

@Retention (RetentionPolicy.RUNTIME)
@interface Hashingsnr {
    String str();
    int yuiop();
    double fdfd();
}


public class German_by_Descent {
    @Hashingsnr(str = "Annotation Example", yuiop = 100, fdfd = 4.267)
    public void mymeth(){
              German_by_Descent ob = new German_by_Descent();
try{
    Class c = ob.getClass();
    Method m = c.getMethod("mymeth");
    Hashingsnr anno = m.getAnnotation(Hashingsnr.class);
    System.out.println(anno.str() + " " + anno.yuiop() + " " + anno.fdfd());

}catch(NoSuchMethodException exc){
    System.out.println("Method Not Found");
}
}
public static void main(String[] args) {

   German_by_Descent ogb = new German_by_Descent();

    ogb.mymeth();

}

}

Answer 1

Your program seems to be working correctly. I get the following output when i run it…

run-single:
Annotation Example 100 4.267
BUILD SUCCESSFUL (total time: 12 seconds)

I’m i missing something in your question?

I also changed the code to use the getAnnotations() method and recieved the same result…

final Annotation[] annos = m.getAnnotations();

for (Annotation anno : annos) {
    if (anno instanceof Hashingsnr) {
        final Hashingsnr impl = (Hashingsnr)anno;
        System.out.println(impl.str() + " " + impl.yuiop() + " " + impl.fdfd());
    }
}