With reified generics, the code

  class Foo<X> {
    X x;
  }

  Foo<int> fooInt;
  fooInt.x = 5;
  Foo<float> fooFloat;
  fooFloat.x = 5.0;

compiles to:

  class Foo_int {
    int x;
  }

  class Foo_float {
    float x;
  }

  Foo_int fooInt;
  fooInt.x = 5;
  Foo_float fooFloat;
  fooFloat.x = 5.0;

On the other hand, erased generics compiles to this:

  class Foo {
    void* x;
  }

  Foo fooInt;
  fooInt.x = new int(5);
  Foo fooFloat;
  fooFloat.x = new float(5.0);