Tranparency using JNA libraries stops to work. It works on JDK 1.6u3 and prior versions
The test case to reproduce the problem:

1) https://jna.dev.java.net/ -> 'documents and files' -> 'latest' -> download jna.jar + examples.jar

2) run the following test:

import javax.swing.JFrame;
import com.sun.jna.examples.WindowUtils;
public class test{
   public static final void main(String args[]){
   JFrame fr = new JFrame();
   fr.setBounds(100,100,200,200);
   WindowUtils.setWindowTransparent(fr, true);
   fr.setVisible(true);
   }
}