RFR: 8273581: Change the mechanism by which JDK loads the platform-specific FontManager class [v4]

[Prasanta Sadhukhan]

On Fri, 17 Sep 2021 12:37:34 GMT, Alexander Scherbatiy <alexsch at openjdk.org> wrote:

>> FontManagerFactory class uses reflection to load platform specific FontManager classes from "sun.font.fontmanager" property.
>> 
>> Fix proposes creating FontManager platform specific classes directly in the similar way as it has been already done for GraphicsEnvironment and AWT Toolkit ([JDK-8130266](https://bugs.openjdk.java.net/browse/JDK-8130266) and [JDK-8212700](https://bugs.openjdk.java.net/browse/JDK-8212700)).
>> 
>> FontManager is internal jdk class. It is placed in `sun.font` package and java modularization encapsulates  FontManager from subclassing and using by a user.
>> 
>> The fix reuses PlatformGraphicsInfo to create FontManager platform specific classes. May be FontManager creation code needs to be placed in its own info classes.
>
> Alexander Scherbatiy has updated the pull request incrementally with four additional commits since the last revision:
> 
>  - Remove obsolete imports from FontManagerFactory
>  - Change synchronized to DCL in FontManagerFactory singleton
>  - Run CheckFontManagerSystemProperty test in headless mode
>  - Remove @SuppressWarnings(removal)

src/java.desktop/share/classes/sun/font/FontManagerFactory.java line 32:

> 30:  * platform.
> 31:  *
> 32:  * A default implementation is given for Linux, Solaris and Windows.

Should we also remove mention of Solaris from here (due to JEP381) not being supported in mainline?

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PR: https://git.openjdk.java.net/jdk/pull/5517