Enabling GTK3 on Linux

GTK+, formally known as the GIMP toolbox, is a cross-platform tool used for creating graphical user interfaces. The tool consists of widgets accessible through its API. Java's enhancement ensures GTK 2 and GTK 3 are supported on Linux when developing Java applications with graphical components. The implementation supports Java apps that employ JavaFX, AWT, and Swing.

We can create Java graphical applications with JavaFX, AWT, and Swing. Here is a table summarizing those three approaches as they relate to GTK, prior to Java 9:

Approach	Remarks
JavaFX	Uses a dynamic GTK function lookup Interacts with AWT and Swing via JFXPanel Uses AWT printing functionality
AWT	Uses a dynamic GTK function lookup
Swing	Uses a dynamic GTK function lookup

So, what changes were necessary to implement this enhancement? For JavaFX, three specific...