The initial solution kept these three in full sync at all times:
contentType field, characterEncoding field, 'Content-Type' header.
That is correct behavior, however it breaks existing tests that rely
on contentType and characterEncoding being equal to exactly what
they were set to.
For example, consider:
response.setContentType("text/plain");
response.setCharacterEncoding("UTF-8");
Ideally both contentType and the 'Content-Type' header would now be
"text/plain;charset=UTF-8". However, existing tests would expect
that contentType is equal to "text/plain".
To avoid breaking existing tests, contentType and characterEncoding
will continue to be equal to exactly what they were set to while
the 'Content-Type' header will always include both the content
type and the charset.
The only exception to this rule is when a 'Content-Type' header
is set explicitly, the contentType and characterEncoding fields will
be updated accordingly, possibly overriding the existing values.
Rossen Stoyanchev