RFR: 8282473: Refactor swing classes javadoc to use @throws instead of @exception

[Alexey Ivanov]

On Tue, 1 Mar 2022 10:16:16 GMT, Prasanta Sadhukhan <psadhukhan at openjdk.org> wrote:

> Prevailing JDK coding practices use "@throws" rather than "@exception".
> Refactor existing swing classes javadoc to use @throws

Submitted:

- [JDK-8282539](https://bugs.openjdk.java.net/browse/JDK-8282539): Remove ending punctuation from @throws HeadlessException
- [JDK-8282546](https://bugs.openjdk.java.net/browse/JDK-8282546): Remove ending punctuation from @throws in java.desktop

I decided to separate these two cases.

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PR: https://git.openjdk.java.net/jdk/pull/7644