Java Collection question<E>

[hoboy]

I have read this link
http://download.java.net/jdk7/docs/api/java/util/Collection.html
in order to understand an example I have seen
in the example there is a this method,
public < T extends Response> void excute(Action<T>action)
from the link upward I have looked at
addAll(Collection<? extends E> c)
but still I don't understand this <T extends Response>,
is this mean what I suspect ?
that T is a sub class of Response ?

[Habbit]

Indeed, the "extends Response" puts an upper bound on the type T: it must be a subtype of Response (note that this includes Response itself). The other type of constraint available reads "T super U", where T must be either U or a supertype (up to Object).

Note that if the T type itself is not required (most of the time), you can avoid the generic method and just use a wildcard like the Collection interface does: "public void execute(Action<? extends Response>action)".

[hoboy]

Indeed, the "extends Response" puts an upper bound on the type T: it must be a subtype of Response (note that this includes Response itself). The other type of constraint available reads "T super U", where T must be either U or a supertype (up to Object).

Note that if the T type itself is not required (most of the time), you can avoid the generic method and just use a wildcard like the Collection interface does: "public void execute(Action<? extends Response>action)".

Thanks very much, that has clarified thinks