Question

I know, its a stupid question, but someone told me that we can write a code in an interface, i mean not a logic but System.out.println(), in an interface..

Is this true??

Answer 1

One thing has been forgotten, an interface can have static classes and interfaces , such as ;

public interface MyInterface {
      public static class Holder {};
}

EDIT

JLS states that,

Interfaces may contain member type
declarations (§8.5). A member type
declaration in an interface is
implicitly static and public.