How to get annotation in object java

First of all, you need to change annotation retention to RUNTIME (default is CLASS), so they may be read reflectively. Change to like this:

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
public @interface HolaAn {

    String message();

}

You are trying to get annotation from the class, but your annotation are on a field, the only element target. In this example, you are able to get the annotation in this way:

@HolaAn(message = "MUNDO")
private Hola hola;

@Test
public void testMessageOnField() {
    final Field[] fields = HolaTest.class.getDeclaredFields();
    for (final Field field : fields) {
        if (field.isAnnotationPresent(HolaAn.class)) {
            final HolaAn annotation = field.getAnnotation(HolaAn.class);
            Assert.assertTrue(annotation.message().equals("MUNDO"));
        }
    }
}

If you need to get the annotation from the class, change it to something like this:

@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.FIELD, ElementType.TYPE})
public @interface HolaAn {

    String message();

}

Then, you are able to get annotation message like this:

@HolaAn(message = "CLASS")
public class Hola {

    public Hola() {
        final String message = this.getClass().getAnnotation(HolaAn.class).message();
        System.out.println(message);
    }

}

@Test
public void testMessage() {
    hola = new Hola();
}

Or:

@Test
public void testMessageSecondWay() {
    hola = new Hola();
    final Class<?> theClass = hola.getClass();
    if (theClass.isAnnotationPresent(HolaAn.class)) {
        final HolaAn annotation = theClass.getAnnotation(HolaAn.class);
        Assert.assertTrue(annotation.message().equals("CLASS"));
    }
}

You should change your annotation to

@Target({ ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@interface HolaAn {
    String getMessage();
}

This is necessary to compile the annotation to the classfile.

Now you can access your message via:

Field declaredField = new MessageTest().getClass().getDeclaredField(
        "hola");
System.out.println((declaredField.getDeclaredAnnotation(HolaAn.class)
        .getMessage()));