Bug 153378 [Regression]Label text won't show up when the text key is not found
Steps to reproduce: 1.Add a label, set text to "aaa" 2.Add a resource file "a" to the report, add a text key "k1" which is not in the a.properties to the label 3.Preview in Web Viewer Expected result: Label display "aaa" when the text key is not found Actual result: Nothing in preview
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/util/ParameterValidationUtil.java
*            the message key
	 * @return the message if found, otherwise the message key
	 */
	static private String getMessage( ULocale locale, String key )
	{
		
		String packageName = ModelMessages.class.getName( ).substring( 0,
				ModelMessages.class.getName( ).lastIndexOf( "." ) ); 
		UResourceBundle resourceBundle = UResourceBundle.getBundleInstance(
				packageName + ".Messages", 
				locale, ModelMessages.class.getClassLoader( ) );
		if ( resourceBundle != null )
			return resourceBundle.getString( key );
		return key;
	}
	/**
	 * Validates the input date time string with the given format. The format
	 * can be pre-defined choices or the pattern string.
	 * 
	 * @param format
	 *            the format to validate
	 * @param value
	 *            the value to validate
	 * @param locale
	 *            the locale information
	 * @return the date value if validation is successful
	 * @throws ValidationValueException
	 *             if the value to validate is invalid
	 */
	static private Date doValidateDateTimeByPattern( String format,