<Swing Dev> Fwd: Thread safety of SunFontManager.platformFontMap

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<Swing Dev> Fwd: Thread safety of SunFontManager.platformFontMap

Andrey Turbanov
Hello.
I recently found suspicious field (with SpotBugs help) in class SunFontManager:

    static HashMap<String, FamilyDescription> platformFontMap;

This HashMap is accessed (read and write) in a method
sun.font.SunFontManager#findFontFromPlatformMap. As I see there is no
synchronization when this HashMap is accessed.
This method can be called from client code with this simple stack trace:

      at sun.font.SunFontManager.findFontFromPlatformMap(SunFontManager.java:1508)
      at sun.font.SunFontManager.findFont2D(SunFontManager.java:2069)
      at java.awt.Font.getFont2D(Font.java:500)
      at java.awt.Font.getPSName(Font.java:1416)

I wonder if this unsynchronized access is expected. Looks like it can
break things when accessed from multiple threads simultaneously.
Do I miss something? Is it done this way, because Font objects are
supposed to be accessed from a single thread only?

Andrey Turbanov
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Re: <Swing Dev> Fwd: Thread safety of SunFontManager.platformFontMap

Philip Race
Please re-raise this issue on the correct list which is 2d-dev

-phil.

On 2/16/21 11:02 PM, Andrey Turbanov wrote:

> Hello.
> I recently found suspicious field (with SpotBugs help) in class SunFontManager:
>
>      static HashMap<String, FamilyDescription> platformFontMap;
>
> This HashMap is accessed (read and write) in a method
> sun.font.SunFontManager#findFontFromPlatformMap. As I see there is no
> synchronization when this HashMap is accessed.
> This method can be called from client code with this simple stack trace:
>
>        at sun.font.SunFontManager.findFontFromPlatformMap(SunFontManager.java:1508)
>        at sun.font.SunFontManager.findFont2D(SunFontManager.java:2069)
>        at java.awt.Font.getFont2D(Font.java:500)
>        at java.awt.Font.getPSName(Font.java:1416)
>
> I wonder if this unsynchronized access is expected. Looks like it can
> break things when accessed from multiple threads simultaneously.
> Do I miss something? Is it done this way, because Font objects are
> supposed to be accessed from a single thread only?
>
> Andrey Turbanov