Newer versions of Linux, Solaris, and other Unix flavor desktop
environments use GTK3, while still supporting GTK2.

Previously, the JDK would default to loading the older GTK2 libraries.
However, in this release, it defaults to loading GTK3 libraries.
Loading is typically triggered by using the Swing GTK Look And Feel.

If, for any reason, this causes issues for an application, the old
behavior can be restored by using the system property:
`-Djdk.gtk.version=2.2`