Java generics - is it possible to restrict T to be Serializable?

Question

Is it possible to make something like this? I know that implements cannot be in the <>, but I want to restrict the T to be Serializable somehow.

public class Clazz<T implements Serializable> {
    ...
}

I tried `extends` but I had an error so I thought it was wrong. Then I found there was another issue and `extends` really works. — user219882, Aug 16 '11 at 11:56
possible duplicate of [Java generics - why is “extends T” allowed but not “implements T”?](https://stackoverflow.com/questions/976441/java-generics-why-is-extends-t-allowed-but-not-implements-t) — Roeland Van Heddegem, Oct 13 '17 at 13:33

score 30 · Accepted Answer · answered Aug 16 '11 at 10:55

30

public class Clazz<T extends Serializable> {
    ...
}

answered Aug 16 '11 at 10:55

Heisenbug

score 6 · Answer 2 · answered Aug 16 '11 at 10:55

6

Just use extends instead of implements.

answered Aug 16 '11 at 10:55

Ingo

score 4 · Answer 3 · answered Aug 16 '11 at 10:56

4

Yes, just use extends instead of implements.

answered Aug 16 '11 at 10:56

Perception

3 Answers3