Java generics and Array's

Question

The following snippet makes sense yet when I run this against my unit test.. I get a ClassCastException (Object can\'t be cast to String) on the line marked with \'>>>>\'.

Answer 1

you're casting Object to String, IOW, a super class to the inherited one. It is always prohibited. As AlexR suggested, make use of Arrays.newInstance(). But in that case you would have to pass a class of your object as here:

ArrayUtils.append(array, "b", String.class);

I suggest you not to try implementing this standard behaviour of dynamically extended array : it has been already implemented in ArrayList class. You can checkout the source to learn how it is dealing with generics.