RFR: 8336382: Fixes error reporting in loading AWT and fonts [v2]

[Karm Michal Babacek]

> If there is a problem with finding and calling e.g. `java/awt/GraphicsEnvironment` in `AWTIsHeadless`, the env' Exception remains set and it is not cleared. Later, that manifests as:
> 
>     Fatal error reported via JNI: Could not allocate library name
> 
> Which is misleading. The code path is perhaps rare in a normal JDK usage, but it has been complicating our users' bug reports in the GraalVM/native-image ecosystem for quite some time.
> 
> Instead of failing later indicating that the user has incorrectly configured JNI, it bails out very soon with a message that seems as if a jstring could not have been allocated. It sends users on wild goose chases where it appears `JNU_NewStringPlatform` calls failed,  e.g.
> 
> * https://github.com/oracle/graal/issues/9138
> * https://github.com/oracle/graal/issues/8475
> * https://github.com/oracle/graal/issues/9300
> * https://github.com/quarkusio/quarkus/issues/31596
> * https://github.com/graalvm/mandrel/issues/292
> * https://github.com/Karm/mandrel-integration-tests/issues/262
> 
> This commit fixes the error reporting in the AWTIsHeadless.
> 
> Furthermore, when AOT compiled, there is little sense for having a JAVA_HOME, yet some parts of AWT code look for it to search fonts. In such case, an empty directory structure is enough to accommodate it, e.g.
> 
> /tmp/JAVA_HOME/
> /tmp/JAVA_HOME/conf
> /tmp/JAVA_HOME/conf/fonts
> /tmp/JAVA_HOME/lib
> 
> The exception is somewhat cryptic for users again, merely stating:
> 
>     Exception in thread "main" java.io.IOException: Problem reading font data.
>         at java.desktop at 22.0.1/java.awt.Font.createFont0(Font.java:1205)
>         at java.desktop at 22.0.1/java.awt.Font.createFont(Font.java:1076)
>         at imageio.Main.loadFonts(Main.java:139
> 
> Adding the cause there makes it clearer, i.e. that JAVA_HOME might be missing:
> 
>     Exception in thread "main" java.io.IOException: Problem reading font data.
>         at java.desktop at 23-internal/java.awt.Font.createFont0(Font.java:1206)
>         at java.desktop at 23-internal/java.awt.Font.createFont(Font.java:1076)
>         at imageio.Main.loadFonts(Main.java:139)
>         at imageio.Main.paintRectangles(Main.java:97)
>         at imageio.Main.main(Main.java:195)
>         at java.base at 23-internal/java.lang.invoke.LambdaForm$DMH/sa346b79c.invokeStaticInit(LambdaForm$DMH)
>     Caused by: java.lang.Error: java.home property not set
>         at java.desktop at 23-internal/sun.awt.FontConfiguration.findFontConfigFile(FontConfiguration.java:180)
>         at java.desktop at 23-internal/sun.awt.FontConf...

Karm Michal Babacek has updated the pull request incrementally with one additional commit since the last revision:

  Reverts changes to java/awt/Font.java

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/20169/files
  - new: https://git.openjdk.org/jdk/pull/20169/files/9d0c671e..49c6ebdd

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20169&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20169&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/20169.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20169/head:pull/20169

PR: https://git.openjdk.org/jdk/pull/20169