上课 <Foo<T> &gt;在运行时给出通用类型输入

Question

I know there are a lot of questions about similar issues already, but I haven't found one to directly address this one.

Here is the skeleton of the code I'm trying to implement:

class MyObj<T> {
    // Internals are unimportant ...
}

private <T> void foo(T arg) {
    Class<MyObj<T>> clazz = // What do I write here?

    // Here is one thing that works, but is quite ugly:
    @SuppressWarnings("unchecked")
    clazz = (Class<MyObj<T>>)(new MyObj<T>().getClass())

    // ...

    // Later, clazz is passed to a constructor of some other class
    OtherClass<MyObj<T>> foo = new OtherClass<>(clazz);
}

Question 1: Does anyone have a better suggestion of how to populate clazz ? Ideally, it would avoid calling new .

Question 2: Given the ugly (but working) code above, are there any situations where it could break? I don't like to @SuppressWarnings , and worry about problems I might be hiding.

Answer 1

To avoid instantiating, you can write:

Class<MyObj<T>> clazz = (Class) MyObj.class;

Due to erasure, there exists a single Class instance for MyObj , regardless of whatever type parameters it might have, so although this is ugly, it is safe.