code: private boolean shouldInterpretEmptyStringSubmittedValuesAsNullClearInput(FacesContext context)
     {
         ExternalContext ec = context.getExternalContext();
        
         // parses the web.xml to get the
         // "org.apache.myfaces.INTERPRET_EMPTY_STRING_SUBMITTED_VALUES_AS_NULL_CLEAR_INPUT" value
         String param = ec.getInitParameter(EMPTY_VALUES_AS_NULL_CLEAR_INPUT_PARAM_NAME);
         
         // evaluate the param
         Boolean interpretEmptyStringAsNullClearInput = "true".equalsIgnoreCase(param);
         
         return interpretEmptyStringAsNullClearInput;
     }
docs: Get the value of context parameter
  org.apache.myfaces.INTERPRET_EMPTY_STRING_SUBMITTED_VALUES_AS_NULL_CLEAR_INPUT from the web.xml
  
  @return the value of the context parameter