You can't due to type erasure.
Java generics are little more than syntactic sugar for Object casts. To demonstrate:
List list1 = new ArrayList();
List list2 = (List)list1;
list2.add("foo"); // perfectly legal
The only instance where generic type information is retained at runtime is with
Field.getGenericType() if interrogating a class's members via reflection.
All of this is why
Object.getClass() has this signature:
public final native Class> getClass();
The important part being
To put it another way, from the Java Generics FAQ:
Why is there no class literal for concrete parameterized types?
Because parameterized type has no exact runtime type representation.
A class literal denotes a
object that represents a given type.
For instance, the class literal
String.class denotes the
object that represents the type
String and is identical to the
Class object that is returned when
getClass is invoked on a
String object. A class literal can
be used for runtime type checks and
Parameterized types lose their type
arguments when they are translated to
byte code during compilation in a
process called type erasure . As a
side effect of type erasure, all
instantiations of a generic type share
the same runtime representation,
namely that of the corresponding raw
type . In other words, parameterized
types do not have type representation
of their own. Consequently, there is
no point in forming class literals
, since no such
Class objects exist.
Only the raw type
List has a
object that represents its runtime
type. It is referred to as