How does hibernate determine type of an empty collection elements?

Question

Consider we've got an instance of a class like this:
@Entity
class MyClass {
@ManyToMany
List<MyClass2> theList = new LinkedList<MyClass2>();
public List<MyClass2> getTheList() { return theList; }
public void setTheList( List<MyClass2> theList ) { this.theList = theList; }
.. id and its getter and setter here ..
As far as I know generic collection's type is erased after compilation. Therefore hibernate sees a raw-type collection in runtime. But it maps this many-to-many association from MyClass to MyClass2 correctly even if the list is empty. And in java persistence API documentation "targetEntity" property in @ManyToMany is optional also. It says "Default: the parameterized type of the Collection when defined using generics".
So there should be another way to determine collection element's type in runtime. Could anybody explain it to me?

Answer 1

The compiled class file still contains the information. Therefore you can get the generic type information for fields (using Field.getGenericType).
Objects on the other hand, don't contain that information.