RFR: 8371091: Improve the exception message of NullPointerException thrown by the methods in the default implementation of HttpRequest.Builder [v4]

[Daniel Fuchs]

On Tue, 4 Nov 2025 11:37:13 GMT, EunHyunsu <duke at openjdk.org> wrote:

>> This change adds clearer NullPointerException messages to the POST(), PUT(), and method() methods in HttpRequest.Builder when the provided BodyPublisher is null.
>> 
>> Each of these methods now calls `requireNonNull(body, "BodyPublisher must not be null")`, making the exception message explicit.
>> A corresponding regression test (RequestBuilderNullBodyTest) has been added to verify this behavior.
>> 
>> All builds and related tests (jdk/java/net/httpclient) have passed successfully.
>> 
>> Currently, only POST(), PUT(), and method() include these messages.
>> Some other builder methods (such as header(), setHeader()) also throw NullPointerException without a message.
>> I would like to discuss whether adding consistent messages to those methods would be beneficial,
>> and whether the current wording "BodyPublisher must not be null" feels appropriate.
>
> EunHyunsu has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8371091: Add testNullMessages() to HttpRequestBuilderTest and fix whitespaces error

I ran HttpClient tests in the CI and they came back green. 
So look good to  me!

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Marked as reviewed by dfuchs (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/28103#pullrequestreview-3428977186