<AWT Dev> [9] Review request for 8048289 Gtk: call to UIManager.getSystemLookAndFeelClassName() leads to crash

[Alexander Zvegintsev]

Hello AWT team,

please review the fix
http://cr.openjdk.java.net/~azvegint/jdk/9/8048289/00/
for the issue
https://bugs.openjdk.java.net/browse/JDK-8048289

UIManager.getSystemLookAndFeelClassName() calls 
UNIXToolkit.isNativeGTKAvailable()
which loads gtk library, checks version, and closes library. Thread 
specific data key is created upon gtk dlopen,
but this key is not deleted at dlclose. This produces a crash at thread 
termination.

So this fix is a workaround for the glib issue [1], it simply doesn't 
close library.
Simple case to reproduce this issue written on C is attached to [1].

[1] https://bugzilla.gnome.org/show_bug.cgi?id=733065

-- 
Thanks,

Alexander.