Why would I use java.lang.Class.cast [duplicate]

Answer 1

I don't think it's often used exactly as you have shown. Most common use I have seen is where folks using generics are trying to do the equivalent of this:

public static  T castToNumber(Object o) {
    return (T)o;
}

Which doesn't really do anything useful because of type erasure.

Whereas this works, and is type safe (modulo ClassCastExceptions):

public static  T castToNumber(Object o, Class clazz) {
    return clazz.cast(o);
}

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EDIT: Couple of examples of use from google guava:

• MutableClassToInstanceMap
• Cute use in Throwables#propagateIfInstanceOf, for type safe generic throw spec