code: public void setContextName(final String contextName) {
  		NullArgumentException.validateNotNull(contextName, "Context name");
  		this.contextName = contextName;
  
  		// remove the previous setting.
  		WebAppInitParam prev = getWebAppInitParam("webapp.context");
  		if (prev != null) {
  			contextParams.remove(prev);
  		}
  
  		// set the context name into the context params
  		final WebAppInitParam initParam = new WebAppInitParam();
  		initParam.setParamName("webapp.context");
  		initParam.setParamValue(contextName);
  		contextParams.add(initParam);
  	}
docs: Setter.
  
  @param contextName value to set. Cannot be null.
  @throws NullArgumentException if context name is null