code: private ConfigPropertiesSource initConfigPropertiesSource(ServletContext context, Properties configProps)
  			throws ServletException {
  
  		String configLocation = getInitParameter("configLocation");
  		String configPropsSourceClass = getInitParameter("configPropertiesSourceClass");
  		if (null == configProps && null == configLocation && null == configPropsSourceClass)
  			throw new ServletException("Neither configLocation nor configPropertiesSourceClass init params were set."
  					+ " You must set at least the configLocation param. Please check your web.xml file");
  
  		// Initialize the config properties source that will provide with all
  		// configuration options.
  		ConfigPropertiesSource propsSrc = null;
  
  		// Load a custom class to set config properties
  		if (null != configPropsSourceClass) {
  			propsSrc = (ConfigPropertiesSource) ClassLoaderResourceUtils.buildObjectInstance(configPropsSourceClass);
  			if (propsSrc instanceof ServletContextAware) {
  				((ServletContextAware) propsSrc).setServletContext(context);
  			}
  		} else if (configLocation == null && configProps != null) {
  
  			// configuration retrieved from the in memory configuration
  			// properties
  			propsSrc = new PropsConfigPropertiesSource(configProps);
  
  		} else {
  			// Default config properties source, reads from a .properties file
  			// in the classpath.
  			propsSrc = new PropsFilePropertiesSource();
  		}
  
  		// If a custom properties source is a subclass of
  		// PropsFilePropertiesSource, we hand it the configLocation param.
  		// This affects the standard one as well.
  		if (propsSrc instanceof PropsFilePropertiesSource)
  			((PropsFilePropertiesSource) propsSrc).setConfigLocation(configLocation);
  		return propsSrc;
  	}
docs: Initialize the config properties source that will provide with all
  configuration options.
  
  @param context
  the servlet context
  @param configProps
  the config properties
  @return the config properties source
  @throws ServletException
  if an exception occurs