Originally filed as a JavaFX Script bug, this is actually a bug in Nimbus.

Try the following to get a NPE in BasicListUI:

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class BLTest {

    private static void createAndShowGUI(String[] args) {
        try {

UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
        } catch (Exception e) {}

        JList list = new JList();
        list.getBaseline(1, 1);
    }

    public static void main(final String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI(args);
            }
        });
    }
} 


Original description follows:

Logging this for doc (added to cc list).
-------------------
When I run the JavaFXScriptImgSearch2 project (it's the JavaFX Script Image Search program that you did for me). I've attached a zip file that contains the source and the project code. If I try to run the project with JDK 1.6.0_10, it generates a Null Pointer exception as follows:

C:\Program Files\Java\jdk1.6.0_10\bin>java.exe -jar C:\MyNetBeansProjects\JavaFScriptImgSearch2\dist\JavaFXScriptImgSearch2.jar

java.lang.NullPointerException
       at javax.swing.plaf.basic.BasicListUI.getBaseline(BasicListUI.java:470)
       at javax.swing.JComponent.getBaseline(JComponent.java:2530)
       at javax.swing.plaf.basic.BasicScrollPaneUI.getBaseline(BasicScrollPaneI.java:386)
      ...
       at javafx.gui.Window.setWindowVisibility$impl(Window.fx:130)
       at javafx.gui.Frame.setWindowVisibility(Frame.fx:22)
       at javafx.gui.Window.postInit$(Window.fx:170)
       at javafx.gui.Frame.postInit$(Frame.fx:22)
       at javafx.gui.Frame.initialize$(Frame.fx:22)
       at javafxscriptimgsearch2.Main.javafx$run$(Main.fx:89)

However, if I run it in JDK 1.6.0_05, it runs fine.
Posted Date : 2008-06-05 18:15:02.0

N/A

Nimbus is not providing the "List.cellRenderer" key that is used in the getBaseline() method of BasicListUI. We need to fix BasicListUI to work the best it can wothout throwing a NPE if this key is missing. To do that we should change it to use a new instance of DefaultListCellRenderer if  the key is missing.
Posted Date : 2008-06-05 20:44:34.0

This problem happens with HTML in Buttons, too, as well, getBaseline doesn't work. I called getBaseline on the JButton, with 10 and 10 as parameters, and i get this exception : 

Exception in thread "main" java.lang.IllegalArgumentException: Width and height must be >= 0
	at javax.swing.plaf.basic.BasicHTML.getHTMLBaseline(Unknown Source)
	at javax.swing.plaf.synth.SynthButtonUI.getBaseline(Unknown Source)
	at javax.swing.JComponent.getBaseline(Unknown Source)
	at FastTest.main(FastTest.java:34)