import java.awt.*;
import javax.swing.*;
import javax.swing.plaf.*;
import javax.swing.plaf.nimbus.*;

public class JListColorsDoNotImplUIResourceInNimbus {
    public static void main(String[] args) throws Exception {
        UIManager.setLookAndFeel(new NimbusLookAndFeel());
        JList list = new JList();

        Color selBackColor = list.getSelectionBackground();
        if (!(selBackColor instanceof UIResource)) {
            throw new RuntimeException(String.format(
                "JList.getSelectionBackground() returned instance of '%s' instead of UIResource.",
                selBackColor.getClass()));
        }
        Color selForeColor = list.getSelectionForeground();
        if (!(selForeColor instanceof UIResource)) {
            throw new RuntimeException(String.format(
                "JList.getSelectionForeground() returned instance of '%s' instead of UIResource.",
                selForeColor.getClass()));
        }
    }
}