RFR: 8263506: Make sun.net.httpserver.UnmodifiableHeaders unmodifiable [v5]

[Daniel Fuchs]

On Wed, 7 Apr 2021 13:28:32 GMT, Julia Boes <jboes at openjdk.org> wrote:

>> The fix makes the map in sun.net.httpserver.UnmodifiableHeaders unmodifiable by wrapping it in an unmodifiable view.
>
> Julia Boes has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 12 additional commits since the last revision:
> 
>  - Merge branch 'master' into 8263506
>  - fix get method and constructor, add tests
>  - Account for null values and change type in constructor
>  - Merge branch 'master' into 8263506
>  - Merge branch 'master' into 8263506
>  - move constructor call in ExchangeImpl and fix indentation
>  - wrap List<String> with unmodifiable map and update test
>  - remove map wrapping
>  - fix imports
>  - Merge branch 'master' into 8263506
>  - ... and 2 more: https://git.openjdk.java.net/jdk/compare/eed6b83a...4f2247fc

src/jdk.httpserver/share/classes/sun/net/httpserver/UnmodifiableHeaders.java line 42:

> 40:         h.forEach((k, v) -> unmodHeaders.put(k, Collections.unmodifiableList(v)));
> 41:         this.map = Collections.unmodifiableMap(unmodHeaders);
> 42:         this.headers = h;

Now that we have `unmodHeaders` we could simply keep it:

this.headers = unmodHeaders;

we no longer need to keep the original `headers` around.

src/jdk.httpserver/share/classes/sun/net/httpserver/UnmodifiableHeaders.java line 56:

> 54:         List<String> l = headers.get(key);
> 55:         return l == null ? null : Collections.unmodifiableList(l);
> 56:     }

You could simply return `map.get(key)` here - since map is an unmodifiable map wrapping  `unmodHeaders`; Or even `headers.get(key)` if `headers` is `unmodHeaders` as suggested below...

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PR: https://git.openjdk.java.net/jdk/pull/3032