Java: custom toString to fit any class

I want to create a toString() method that works for any class, printing all its attributes as if it worked like this:

String toString(){
    for(Attribute att: this.Attributes){
        System.out.println(att.name + ": " + att.toString());
    }
}

But this would work supposing all attributes have toString() method, so let's keep this supposition.

I guess this question includes concepts of reflection, and I don't know much about this concept nor how to apply this in Java.