Why doesn't Java support generic Throwables?

Question

class Bouncy extends Throwable {     
}
// Error: the generic class Bouncy may not subclass java.lang.Throwable

Why doesn\'t Java

Answer 1

Here are a couple of things you can do:

1. Throwables can implement generic interfaces, as long as the throwable itself has no type parameters, e.g.
   

   interface Bouncy {
    // ...
}
class BouncyString extends Exception implements Bouncy {
    // ...
}

2. A throws clause can refer to type parameters, e.g.

   static void
throwIfInstanceOf(Throwable ex, Class clazz) throws X {
    if (clazz.isInstance(ex)) throw clazz.cast(ex);
}