The spec for the following overriding method
https://docs.oracle.com/javase/8/docs/api/java/nio/CharBuffer.html#chars--
says (as the overridden method)
----------------------------
"Returns a stream of int zero-extending the char values from this sequence.
Returns: an IntStream of char values from this sequence "
----------------------------

The resulting stream is different for buffer instances produced differently:

Consider the following code:

        System.err.println(CharBuffer.allocate(1).put("A").chars().iterator().hasNext());
        System.err.println(CharBuffer.wrap("A").chars().iterator().next());

The output will be 

false
65

Having the current specification of CharBuffer.chars()
and not knowing the whole background of a typical CharBuffer behavior 
stream instance returned by the method might not be perfectly expected.