import java.awt.Color;
import java.awt.Frame;
import java.awt.Label;
import static java.awt.EventQueue.invokeAndWait;

public class AWT {
    public static void main(String[] args) throws Exception {
        invokeAndWait(() -> {
            Frame frame = new Frame();
            frame.add(new Label("TEST"));
            frame.setUndecorated(true);
            frame.setBackground(new Color(0f, 1f, 0f, 0.5f));
            frame.setBounds(200, 200, 200, 200);
            frame.setVisible(true);
        });
    }
}

The code above shows a label with the following cmd:
java -Dsun.java2d.xrender=false AWT

The code above does not show a label with the following cmd:
java -Dsun.java2d.xrender=true AWT