Question

I would like to do something like:

Class<List<String>> targetClass = List<String>.class;

but that construct does not compile.

The compiler is ok with the

Class<List<String>> targetClass;

declaration, but the compiler does not like

List<String>.class

Interestingly, the compiler (1.7) allows this:

Class<List<String>> targetClass = (Class<List<String>>) List.class;

but then of course complains about an unsafe cast.

Answer 1

Although it seems like it should be, List<String> is not a class, so you cannot get the class object for that. Generics are only used to check at compile time. They are erased from the compiled bytecode.

So, the best you can do is just,

Class<List> clz = List.class;

From Effective Java, 2nd ed.,

There are two minor exceptions to the rule that you should not use raw
types in new code, both of which stem from the fact that generic type
information is erased at runtime (Item 25). You must use raw types in
class literals. The specification does not permit the use of
parameterized types (though it does permit array types and primitive
types) [JLS, 15.8.2]. In other words, List.class, String[].class, and
int.class are all legal, but List<String>.class and List<?>.class are
not