[Java][RESTEasy] Make efficient use of entrySet iterator.

[iamolivinius]

@bbdouglas
@JFCote
@sreeshas
@jfiala
@lukoyanov
@cbornet

PR checklist

• Read the contribution guidelines.
• Ran the shell script under ./bin/ to update Petstore sample so that CIs can verify the change. (For instance, only need to run ./bin/{LANG}-petstore.sh and ./bin/security/{LANG}-petstore.sh if updating the {LANG} (e.g. php, ruby, python, etc) code generator or {LANG} client's mustache templates). Windows batch files can be found in .\bin\windows\.
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Description of the PR

The original method accesses the value of a Map entry, using a key that was retrieved from a keySet iterator. It is more efficient to use an iterator on the entrySet of the map, to avoid the Map.get(key) lookup.

http://findbugs.sourceforge.net/bugDescriptions.html#WMI_WRONG_MAP_ITERATOR

[wing328]

Thanks for the PR but your commit (as shown in the Commits tab) is not linked to your Github account, which means this PR won't count as your contribution in https://github.com/swagger-api/swagger-codegen/graphs/contributors.

Let me know if you need help fixing it.

Ref: https://github.com/swagger-api/swagger-codegen/wiki/FAQ#how-can-i-update-commits-that-are-not-linked-to-my-github-account

[iamolivinius]

@wing328

I added the email address to my gh account.

[wing328]

@iamolivinius looks good now 👍