Java Generics with Class

Question

So I have a map:

Map format = new HashMap();

And I would add elements to it like this:

Answer 1

It is strange for me, that your compiler on line

Integer i = verifyType("100",format.get("Vendor Number"));

complains about unchecked invocation but doesn't show an error like "Type mismatch: cannot convert from Object to Integer".

This line just doesn't make sense to me. What do you expect verifyType to return if it receives Date.class as a second parameter? Also an Integer (then the return type of verifyType is invalid)? Or a Date? If you expect a Date, how is compiler expected to know that

format.get("Vendor Number");

returns Integer.class, but

format.get("Vendor Dispatch");

returns Date.class

Invocation of

Integer i = verifyType("100",format.get("Vendor Dispatch"));

must fail, as Date is not an Integer. So, in my opinion (and in opinion of my compiler) compilation of

Integer i = verifyType("100",format.get("Vendor Number"));

must fail.