generics - Getting T.class despite Java's type-erasure

Question

I'm trying to bind an interface to its implementation as read from a configuration file so that I can feed it to my IoC container. Here's roughly what I'm trying to do:

public class PropertyImplementationBinder<T> {
    // ...
    public Class getInterfaceClass() {
        return T.class; // OR Class<T>, note T is not newable
    }
    public Class getImplementationClass() {
        return /* read config file to get implementation class */;
    }
}

Is it somehow possible to get T.class?

Answer 1

You need to explicitly pass the class into the constructor (and store it yourself).

private final Class<T> clazz;

PropertyImplementationBinder(Class<T> clazz){
    this.clazz = clazz;
}

public Class<T> getInterfaceClass() {
    return clazz;
}