Bug 6969 NPE in code formatter preference page
20011206 Open the code formatter preference page Go to the style tab Go to the number of spaces... field Backspace until the field is empty NPE
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/CodeFormatterPreferencePage.java
private void updatePreview() {
		fPreviewDocument.set(new CodeFormatter(fWorkingValues).format(fPreviewText));
	}	
	
	private void updateControls() {
		
		for (int i= fCheckBoxes.size() - 1; i >= 0; i--) {
			Button curr= (Button) fCheckBoxes.get(i);
			ControlData data= (ControlData) curr.getData();
					
			String currValue= (String) fWorkingValues.get(data.getKey());	
			curr.setSelection(data.getSelection(currValue) == 0);			
		}
		for (int i= fTextBoxes.size() - 1; i >= 0; i--) {
			Text curr= (Text) fTextBoxes.get(i);
			String key= (String) curr.getData();		
			String currValue= (String) fWorkingValues.get(key);
			curr.setText(currValue);
		}
	}
	
	private IStatus validatePositiveNumber(String number) {
		StatusInfo status= new StatusInfo();
		if (number.length() == 0) {
			status.setError(JavaUIMessages.getString("CodeFormatterPreferencePage.empty_input"));
		} else {
			try {
				int value= Integer.parseInt(number);
				if (value < 0) {
					status.setError(JavaUIMessages.getFormattedString("CodeFormatterPreferencePage.invalid_input", number));