an interview question

[Raja seemakurthi]

is it possible to return an interface reference type by a any java method?

[Henry Wong]

Originally posted by Raja seemakurthi:
is it possible to return an interface reference type by a any java method?

Do you mean something like this?

public List returnListInterface() {
    return new ArrayList();
}

Henry

[Raja seemakurthi]

yes, exactly i want that only.

he asked me whether we can return a List type from a method.
later he asked me other quesstion, ie.... if a method can return an interface type then , is it feature of OOPS ar Java?


i said this is OOPs feature only.

[Stan James]

See if you can do a quick survey and tell how many languages have something comparable to Java's interface. The concept of a pure abstract type like that has been around, but Kent Beck's Implementation Patterns says something like Java is one of the first "mainstream, commercially successful" languages to have "interface" in the language.

I just had to look back at a Turbo Pascal program ... it had "Interface" and "Implementation" keywords to mark off blocks of code even before OO, but I don't recall them being polymorphic.