RFR: 8215788: Clarify JarInputStream Manifest access [v4]

[Lance Andersen]

On Fri, 16 Sep 2022 13:06:28 GMT, Alan Bateman <alanb at openjdk.org> wrote:

>> Lance Andersen has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Address latest input regarding wording
>
> src/java.base/share/classes/java/util/jar/JarInputStream.java line 44:
> 
>> 42:  * The {@link #getManifest} method will return the {@code Manifest} when it is
>> 43:  * the first entry in the stream, or {@code META-INF/} is the first entry and
>> 44:  * the {@code Manifest} is the second entry within the stream.
> 
> "within the stream" should probably be "in the stream" to be consistent the first part of the sentence.

Updated as you suggested

> src/java.base/share/classes/java/util/jar/JarInputStream.java line 51:
> 
>> 49:  * If {@code META-INF/} is the first entry in the input stream it will be
>> 50:  * also not be returned by {@link #getNextEntry()} and
>> 51:  * {@link #getNextJarEntry()}.
> 
> JAR files will almost always have the manifest as the first or second entry. It's very hazardous to have getNextEntry/getNextJarEntry work differently when the manifest is present but not at the start. This makes it really hard to specify too. I wonder what the impact would be of changing the implementation so that getNextEntry/getNextJarEntry consistently skip the manifest rather than only when it's at the start. I can't think of anything right now that could dependent on the current behavior where it might or might be returned.

I tend to agree but am reluctant to change 20+ year behavior via this PR as we don't know what we don't know.

> src/java.base/share/classes/java/util/jar/JarInputStream.java line 78:
> 
>> 76:  *  the signers.
>> 77:  * <p>
>> 78:  * <b>Note:</b> If a {@code JarEntry} is modified after the JAR file is signed,
> 
> Can this be an apiNote?

Sure Updated as suggested

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PR: https://git.openjdk.org/jdk/pull/10045