Bug 276202 [Forms] NPE if dispose() called on FormToolkit more than once
Build id: I20090512-2000 java.lang.NullPointerException at org.eclipse.ui.forms.widgets.FormToolkit.dispose(FormToolkit.java:711) At the moment, if you invoke dispose() twice on a FormToolkit instance, an NPE will be thrown. public void dispose() { if (colors.isShared() == false) { colors.dispose(); colors = null; } boldFontHolder.dispose(); } As can be seen, the 'colors' field is set to 'null' which is the cause of the NPE. It's okay to repeatedly invoke dispose() on an SWT widget so I feel this pattern should be extended for a FormToolkit also.
bundles/org.eclipse.ui.forms/src/org/eclipse/ui/forms/widgets/FormToolkit.java
public static final String KEY_DRAW_BORDER = "FormWidgetFactory.drawBorder"; 
	public static final String TREE_BORDER = "treeBorder"; 
	public static final String TEXT_BORDER = "textBorder"; 
	private int borderStyle = SWT.NULL;
	private FormColors colors;
	private int orientation = Window.getDefaultOrientation();
	
	private BorderPainter borderPainter;
	private BoldFontHolder boldFontHolder;
	private HyperlinkGroup hyperlinkGroup;
	
	VisibilityHandler visibilityHandler;
	
	KeyboardHandler keyboardHandler;
	private class BorderPainter implements PaintListener {