Java 5: Generics

[Rohit Bhagwat]

All,

I dont understand why the compiler doesn't give error for the following statement.

List<? extends String> list1 = new ArrayList<String>();

We know that String is a final class and you cannot subclass it. So why doesnt the compiler mark the statement "? extends String" as error?
In my opinion the only reason for not giving error is because it can contain String objects as well which can be valid. Please correct me if I am wrong.

Thank you,
Rohit.

[Matthew Brown]

The compiler doesn't try to work out whether the class can be subclassed when using wildcards, so it will treat that just the same as with any other class. As you say, the collection can hold Strings, so it can be used.

[Javin Paul]

Compiler only verify Type-Safety , so If you insert Integer than it will give error.