А почему не void onPress(); ?
public class Solution {
public static void main(String[] args) throws Exception {
System.out.println(SimpleObject.NAME);
System.out.println(Button.NAME);
}
interface SimpleObject {
String NAME = "SimpleObject";
void onPress();
}
interface Button extends SimpleObject {
final String NAME = "Submit";
String onPress(Object o);
}
}