Validate annotation on getters in Spring 4

How to make delegate fields validation (using annotation) in wrapper? Is it possible to make annotation on getter instead on fields? I tried to do something like this:

class A{
  private Object obj;

  public Object getObj(){
    return obj;
  }

  public void setObj(Object obj){
    this.obj = obj;
  }
}

@Component
class Wrapper{
    A a;

    public Wrapper(A a){
       this.a = a;
    }

    @NotNull
    public getObj(){
       a.getObj();
    }

    public setObj(Object obj){
       a.setObj(obj);
    }
}