Collection.toArray(T[] ), plus from overriding classes, states:

     * @throws ArrayStoreException if the runtime type of the specified array
     * is not a supertype of the runtime type of every element in
     * this collection

 and Stream.toArray(IntFunction<A[]> ) state:

     * @throws ArrayStoreException if the runtime type of the array returned
     * from the array generator is not a supertype of the runtime type of every
     * element in this stream

Rather than "runtime type" it should more accurately be "component type"