If requirement is to show the error in SoapFault from Webservice, you can use below code. Just pass the faultMessage to the method and it will return the SoapFault:

    /**
     * Soap Fault return in case of error 
     * @ chandan Dec 17, 2015
     * @param faultMessage
     * @throws SOAPFaultException
     */
    private void throwSoapFault(String faultMessage) throws SOAPFaultException {
            SOAPFault fa = null;
            try{
                fa = SOAPFactory.newInstance(SOAPConstants.SOAP_1_1_PROTOCOL).createFault(); 
                fa.setFaultCode(new QName(SOAPConstants.URI_NS_SOAP_ENVELOPE, "Sender"));
                fa.setFaultString(faultMessage);
                throw new SOAPFaultException(fa);
            }catch(Exception e2){
                throw new SOAPFaultException(fa);
            }
    }