Get list of fields with annotation, by using reflection

java reflection annotations
user902383 picture user902383 · May 16, 2013 · Viewed 58.8k times · Source

I create my annotation

public @interface MyAnnotation {
}

I put it on fields in my test object

public class TestObject {

    @MyAnnotation 
    final private Outlook outlook;
    @MyAnnotation 
    final private Temperature temperature;
     ...
}

Now I want to get list of all fields with MyAnnotation.

for(Field field  : TestObject.class.getDeclaredFields())
{
    if (field.isAnnotationPresent(MyAnnotation.class))
        {
              //do action
        }
}

But seems like my block do action is never executed, and fields has no annotation as the following code returns 0.

TestObject.class.getDeclaredField("outlook").getAnnotations().length;

Is anyone can help me and tell me what i'm doing wrong?

Answer

Zutty picture Zutty · May 16, 2013

You need to mark the annotation as being available at runtime. Add the following to your annotation code.

@Retention(RetentionPolicy.RUNTIME)
public @interface MyAnnotation {
}

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