Exceptions and Assertions - The Java Programming Language - page 431

super(cause);
}
public BadDataSetException(String details,
Throwable cause) {
super(details, cause);
}
}
Now the catch clause in the example simply becomes:
} catch (IOException e) {
throw new BadDataSetException(e);
} finally {
// ...
}
Not all exception classes provide cause-taking constructors, but all sup-
port the initCause method. To make it easier to use initCause with such
exception classes, it returns the exception instance that it is invoked on.
The idea is that you can use it like this:
throw new BadDataSetException().initCause(e); // Error?
The only problem is that this will nearly always result in a compile-time
error: initCause returns a THRowable instance, and you can only throw a
THRowable if your method's throw clause lists Throwable which it rarely, if
ever, should! Consequently, you have to modify the above, to cast the
Throwable back to the actual exception type you are creating:
throw (BadDataSetException)
new BadDataSetException().initCause(e);