Steps to reproduce:

1) Run Netbeans IDE, version 4.0 beta (see http://www.netbeans.info/downloads/download.php?a=b&p=1&b_bt=1&rv=4.0 for download)

2) JDK 5.0 build starting from b60 (b59 and older work

3) Create some java project (menu File / New project)

4) change Web Browser (menu Tools / Setup Wizard) to Swing HTML
Browser

5) Invoke popup menu over Java Project node (in Projects tab), select
"create Javadoc for Project"

-> never ending NPE rises:

java.lang.NullPointerException
        at javax.swing.text.html.CSS$FontSize.getValue(CSS.java:1672)
        at javax.swing.text.html.CSS$FontSize.toStyleConstants(CSS.java:1805)
        at javax.swing.text.html.StyleSheet$ViewAttributeSet.getAttribute(StyleSheet.java:2630)
        at javax.swing.text.StyleConstants.getFontSize(StyleConstants.java:358)
        at javax.swing.text.html.CSS$FontSize.getValue(CSS.java:1678)
        at javax.swing.text.html.CSS.getFontSize(CSS.java:614)
        at javax.swing.text.html.CSS.getFont(CSS.java:574)
        at javax.swing.text.html.StyleSheet.getFont(StyleSheet.java:867)
        at javax.swing.text.DefaultStyledDocument.getFont(DefaultStyledDocument.java:777)
        at javax.swing.text.LabelView.setPropertiesFromAttributes(LabelView.java:128)
        at javax.swing.text.html.InlineView.setPropertiesFromAttributes(InlineView.java:229)
        at javax.swing.text.LabelView.sync(LabelView.java:39)
        at javax.swing.text.LabelView.getFont(LabelView.java:189)
        at javax.swing.text.GlyphPainter1.sync(GlyphPainter1.java:194)
        at javax.swing.text.GlyphPainter1.getSpan(GlyphPainter1.java:42)
        at javax.swing.text.GlyphView.getPreferredSpan(GlyphView.java:536)
        at javax.swing.text.FlowView$LogicalView.getPreferredSpan(FlowView.java:692)
        at javax.swing.text.FlowView.calculateMinorAxisRequirements(FlowView.java:216)
        at javax.swing.text.html.ParagraphView.calculateMinorAxisRequirements(ParagraphView.java:128)
        at javax.swing.text.BoxView.checkRequests(BoxView.java:911)
        at javax.swing.text.BoxView.getMinimumSpan(BoxView.java:542)
        at javax.swing.text.html.ParagraphView.getMinimumSpan(ParagraphView.java:257)
        at javax.swing.text.BoxView.calculateMinorAxisRequirements(BoxView.java:879)
        at javax.swing.text.html.BlockView.calculateMinorAxisRequirements(BlockView.java:129)
        at javax.swing.text.BoxView.checkRequests(BoxView.java:911)
        at javax.swing.text.BoxView.getMinimumSpan(BoxView.java:542)
        at javax.swing.text.html.BlockView.getMinimumSpan(BlockView.java:362)
        at javax.swing.text.html.TableView.checkSingleColumnCell(TableView.java:434)
        at javax.swing.text.html.TableView.calculateColumnRequirements(TableView.java:397)
        at javax.swing.text.html.TableView.calculateMinorAxisRequirements(TableView.java:519)
        at javax.swing.text.BoxView.checkRequests(BoxView.java:911)
        at javax.swing.text.BoxView.getMinimumSpan(BoxView.java:542)
        at javax.swing.text.BoxView.calculateMinorAxisRequirements(BoxView.java:879)
        at javax.swing.text.html.BlockView.calculateMinorAxisRequirements(BlockView.java:129)
        at javax.swing.text.BoxView.checkRequests(BoxView.java:911)
        at javax.swing.text.BoxView.getMinimumSpan(BoxView.java:542)
        at javax.swing.text.html.BlockView.getMinimumSpan(BlockView.java:362)
        at javax.swing.text.BoxView.calculateMinorAxisRequirements(BoxView.java:879)
        at javax.swing.text.html.BlockView.calculateMinorAxisRequirements(BlockView.java:129)
        at javax.swing.text.BoxView.checkRequests(BoxView.java:911)
        at javax.swing.text.BoxView.setSpanOnAxis(BoxView.java:325)
        at javax.swing.text.BoxView.layout(BoxView.java:682)
        at javax.swing.text.BoxView.setSize(BoxView.java:379)
        at javax.swing.plaf.basic.BasicTextUI$RootView.setSize(BasicTextUI.java:1631)
        at javax.swing.plaf.basic.BasicTextUI.getPreferredSize(BasicTextUI.java:825)
        at javax.swing.JComponent.getPreferredSize(JComponent.java:1582)
        at javax.swing.JEditorPane.getPreferredSize(JEditorPane.java:1227)
        at javax.swing.text.JTextComponent.getPreferredScrollableViewportSize(JTextComponent.java:1712)
        at javax.swing.ViewportLayout.preferredLayoutSize(ViewportLayout.java:75)
        at java.awt.Container.preferredSize(Container.java:1558)
        at java.awt.Container.getPreferredSize(Container.java:1543)
        at javax.swing.JComponent.getPreferredSize(JComponent.java:1584)
        at javax.swing.ScrollPaneLayout.preferredLayoutSize(ScrollPaneLayout.java:475)
        at java.awt.Container.preferredSize(Container.java:1558)
        at java.awt.Container.getPreferredSize(Container.java:1543)
        at javax.swing.JComponent.getPreferredSize(JComponent.java:1584)
        at javax.swing.text.ComponentView$Invalidator.cacheChildSizes(ComponentView.java:404)
        at javax.swing.text.ComponentView$Invalidator.doLayout(ComponentView.java:383)
        at java.awt.Container.validateTree(Container.java:1473)
        at java.awt.Container.validate(Container.java:1448)
        at javax.swing.text.ComponentView$Invalidator.validateIfNecessary(ComponentView.java:396)
        at javax.swing.text.ComponentView$Invalidator.getPreferredSize(ComponentView.java:443)
        at javax.swing.text.ComponentView.getPreferredSpan(ComponentView.java:119)
        at javax.swing.text.BoxView.calculateMajorAxisRequirements(BoxView.java:848)
        at javax.swing.text.BoxView.checkRequests(BoxView.java:906)
        at javax.swing.text.BoxView.getMinimumSpan(BoxView.java:542)
        at javax.swing.text.BoxView.calculateMinorAxisRequirements(BoxView.java:879)
        at javax.swing.text.html.BlockView.calculateMinorAxisRequirements(BlockView.java:129)
        at javax.swing.text.BoxView.checkRequests(BoxView.java:911)
        at javax.swing.text.BoxView.getMinimumSpan(BoxView.java:542)
        at javax.swing.text.html.BlockView.getMinimumSpan(BlockView.java:362)
        at javax.swing.text.BoxView.calculateMinorAxisRequirements(BoxView.java:879)
        at javax.swing.text.html.BlockView.calculateMinorAxisRequirements(BlockView.java:129)
        at javax.swing.text.BoxView.checkRequests(BoxView.java:911)
        at javax.swing.text.BoxView.setSpanOnAxis(BoxView.java:325)
        at javax.swing.text.BoxView.layout(BoxView.java:682)
        at javax.swing.text.BoxView.setSize(BoxView.java:379)
        at javax.swing.plaf.basic.BasicTextUI$RootView.setSize(BasicTextUI.java:1631)
        at javax.swing.plaf.basic.BasicTextUI.getPreferredSize(BasicTextUI.java:825)
        at javax.swing.JComponent.getPreferredSize(JComponent.java:1582)
        at javax.swing.JEditorPane.getPreferredSize(JEditorPane.java:1227)
        at javax.swing.ScrollPaneLayout.layoutContainer(ScrollPaneLayout.java:769)
        at java.awt.Container.layout(Container.java:1401)
        at java.awt.Container.doLayout(Container.java:1390)
        at java.awt.Container.validateTree(Container.java:1473)
        at java.awt.Container.validateTree(Container.java:1480)
        at java.awt.Container.validateTree(Container.java:1480)
        at java.awt.Container.validateTree(Container.java:1480)
        at java.awt.Container.validateTree(Container.java:1480)
        at java.awt.Container.validateTree(Container.java:1480)
        at java.awt.Container.validateTree(Container.java:1480)
        at java.awt.Container.validateTree(Container.java:1480)
        at java.awt.Container.validateTree(Container.java:1480)
        at java.awt.Container.validateTree(Container.java:1480)
        at java.awt.Container.validateTree(Container.java:1480)
        at java.awt.Container.validateTree(Container.java:1480)
        at java.awt.Container.validateTree(Container.java:1480)
        at java.awt.Container.validateTree(Container.java:1480)
        at java.awt.Container.validateTree(Container.java:1480)
        at java.awt.Container.validate(Container.java:1448)
        at javax.swing.RepaintManager.validateInvalidComponents(RepaintManager.java:379)
        at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:113)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:461)
[catch] at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:234)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:163)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:157)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:149)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)

exceptions rises again and again
- try to restart IDE
-> NPE rises again, user can do nothing !