protected MessageHandler buildPopulateSignatureSigningParametersHandler()
        throws ComponentInitializationException {
        val signatureSigningParameters = new PopulateSignatureSigningParametersHandler();
        signatureSigningParameters.setSignatureSigningParametersResolver(
            new DefaultSignatureSigningParametersResolver(signingParametersProvider));
        signatureSigningParameters.initialize();
        return signatureSigningParameters;
    }
<p>buildPopulateSignatureSigningParametersHandler.</p>

@return a {@link MessageHandler} object
@throws ComponentInitializationException if any.
pac4j-saml/src/main/java/org/pac4j/saml/sso/artifact/DefaultSOAPPipelineFactory.java