public void listAppConstant(String constantLabel) throws UnrecognizedCommandException {
		if (null != constantLabel && !"".equals(constantLabel.trim())) {
			try {
				printUsage(constantLabel);
			} catch (NullValueException e) {
			}
		}
		if (null == constantLabel) {
			String[] header = { "Constant", "Description" };
			int labelWidth = header[0].length();
			String[][] text = new String[appConstants.size()][2];
			int i = 0;
			for (Entry<String, AppConstant> entry : appConstants.entrySet()) {
				String label = entry.getKey();
				if (label.length() > labelWidth) labelWidth = label.length();
				text[i][0] = label;
				text[i++][1] = entry.getValue().getDescription();
			}
			int descriptionWidth = TEXT_WIDTH - labelWidth - LABEL_SEP;

			int[] columnWidth = new int[] { labelWidth, descriptionWidth };
			int[] sep = new int[] { LABEL_SEP };
			String str = TextUtilities.generateColumnText(header, text, columnWidth, sep, "", "");
			out.println(str);
		}
	}