Platform: all
JDK: 6, 7

The following code sets minimal Basic L&F descendant and then tries to instantiate JFileChooser.
As the result NPE is thrown and some info is printed to System.err
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import javax.swing.*;
import javax.swing.plaf.basic.*;

public class FileChooserTest {

    public static void main(String[] args) throws Exception {
        SwingUtilities.invokeAndWait(new Runnable() {
            public void run() {
                try {
                    UIManager.setLookAndFeel(new BasicLookAndFeel() {
                        @Override public String getName() { return "A name"; }
                        @Override public String getID() { return "An id"; }
                        @Override public String getDescription() { return "A description"; }
                        @Override public boolean isNativeLookAndFeel() { return false; }
                        @Override public boolean isSupportedLookAndFeel() { return true; }
                    });
                } catch (UnsupportedLookAndFeelException e) {
                    e.printStackTrace();
                }
                new JFileChooser();
            }
        });
    }
}

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For JDK7b103 output is the following

java.lang.NullPointerException
at javax.swing.JFileChooser.updateUI(JFileChooser.java:1794)
at javax.swing.JFileChooser.setup(JFileChooser.java:374)
at javax.swing.JFileChooser.<init>(JFileChooser.java:347)
at javax.swing.JFileChooser.<init>(JFileChooser.java:300)
at FileChooserTest$1.run(FileChooserTest.java:20)

UIDefaults.getUI() failed: no ComponentUI class for: javax.swing.JFileChooser[,0,0,0x0,invalid,alignmentX=0.0,alignmentY=0.0,border=,flags=0,maximumSize=,minimumSize=,preferredSize=,approveButtonText=,currentDirectory=,dialogTitle=,dialogType=OPEN_DIALOG,fileSelectionMode=FILES_ONLY,returnValue=ERROR_OPTION,selectedFile=,useFileHiding=true]
java.lang.Error
at javax.swing.UIDefaults.getUIError(UIDefaults.java:728)
at javax.swing.MultiUIDefaults.getUIError(MultiUIDefaults.java:130)
at javax.swing.UIDefaults.getUI(UIDefaults.java:758)
at javax.swing.UIManager.getUI(UIManager.java:1002)
at javax.swing.JFileChooser.updateUI(JFileChooser.java:1787)
at javax.swing.JFileChooser.setup(JFileChooser.java:374)
at javax.swing.JFileChooser.<init>(JFileChooser.java:347)
at javax.swing.JFileChooser.<init>(JFileChooser.java:300)
at FileChooserTest$1.run(FileChooserTest.java:20)

JCK tests fail because of this problem