Question

How can I write a generic method parameter at my interface method?

public <T extends Mail> T getById(HttpServletResponse response, <ID extends Object> ID);

This line gives me error:

<ID extends Object> ID

Any ideas?

Answer 1

You’re close.

public <T extends Mail, ID> T getById(HttpServletResponse response, ID id) {

Note that extends Object is not a meaningful bound for a wildcard. And declaring ID to be a wildcard on a single method is rarely helpful without any bounds.