When I clicked a button on the JTextComponent, I got NullPointerException.
It happened with JDK1.1.3 + Swing-0.2. However, it worked fine with JDK1.1.2 + Swing-0.2.
As a result of that, the program was stuck.

To reproduce the bug:
run Notepad( one of the Swing-0.2 examples ) with JDK1.1.3.

Here is error message:
Exception occurred during event dispatching:
java.lang.NullPointerException
        at com.sun.java.swing.text.JDocument.positionToLine(JDocument.java:303)
        at com.sun.java.swing.text.JPlainView.modelToView(JPlainView.java:103)
        at com.sun.java.swing.text.JTextUI$JViewFactory.modelToView(JTextUI.java:379)
        at com.sun.java.swing.text.JTextUI$JTextView.modelToView(JTextUI.java:621)
        at com.sun.java.swing.text.JTextUI.modelToView(JTextUI.java:217)
        at com.sun.java.swing.text.JInsertPosition.changeCaretPosition(JInsertPosition.java:351)
        at com.sun.java.swing.text.JInsertPosition.setDot(JInsertPosition.java:304)
        at com.sun.java.swing.text.JInsertPosition.removeUpdate(JInsertPosition.java:182)
        at com.sun.java.swing.text.JDocument.externalNotifyRemove(JDocument.java:506)
        at com.sun.java.swing.text.JDocument.remove(JDocument.java:135)
        at com.sun.java.swing.text.JDocument.remove(JDocument.java:116)
        at com.sun.java.swing.text.JTextComponent.replaceSelection(JTextComponen
t.java:161)
        at com.sun.java.swing.text.JTextComponent$InsertContentAction.actionPerf
ormed(JTextComponent.java:570)
        at com.sun.java.swing.text.JTextController.mapEventToAction(JTextControl
ler.java:216)
        at com.sun.java.swing.text.JTextController.keyPressed(JTextController.ja
va:332)
        at java.awt.Component.processKeyEvent(Component.java:1872)
        at com.sun.java.swing.JComponent.processKeyEvent(JComponent.java:531)
        at java.awt.Component.processEvent(Component.java:1787)
        at java.awt.Container.processEvent(Container.java:792)
        at java.awt.Component.dispatchEventImpl(Component.java:1456)
        at java.awt.Container.dispatchEventImpl(Container.java:837)
        at java.awt.Component.dispatchEvent(Component.java:1393)
        at java.awt.LightweightDispatcher.processKeyEvent(Container.java:1288)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:1274)
        at java.awt.Container.dispatchEventImpl(Container.java:824)
        at java.awt.Window.dispatchEventImpl(Window.java:401)
        at java.awt.Component.dispatchEvent(Component.java:1393)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:63)