<Swing Dev> RFR: 8263481: Specification of JComponent::setDefaultLocale doesn't mention that passing 'null' restores VM's default locale

[Prasanta Sadhukhan]

The current state of specification for
https://docs.oracle.com/en/java/javase/15/docs/api/java.desktop/javax/swing/JComponent.html#setDefaultLocale(java.util.Locale)
doesn't mention anything about passing 'null' as a new default locale.

In fact for OpenJDK implementation passing 'null' restores the default VM's locale. 
This is now explicitly stated in javadoc.

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Commit messages:
 - 8263481: Specification of JComponent::setDefaultLocale doesn't mention that passing 'null' restores VM's default locale

Changes: https://git.openjdk.java.net/jdk/pull/3003/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3003&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8263481
  Stats: 52 lines in 2 files changed: 52 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3003.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3003/head:pull/3003

PR: https://git.openjdk.java.net/jdk/pull/3003