How do I build a Java type object at runtime from a generic type definition and runtime type parameters?

Question

Assuming a generic type declaration (Java)

class Foo {
    public T bar;
}

how can I, at runtime, instantiate a Type object that r

Answer 1

It appeared to be really simpler than most people thought:

Type collectionType = new TypeToken>(){}.getType();
ArrayList persons = gson.fromJson(response, collectionType);

No need to copy ParameterizedTypeImpl class as newacct suggested.