question: public static void registerDefaultResolvers ( ) { List < KeyResolver > keyResolverList = new ArrayList < KeyResolver > ( ) ; keyResolverList . add ( new KeyResolver ( new RSAKeyValueResolver ( ) ) ) ; keyResolverList . add ( new KeyResolver ( new DSAKeyValueResolver ( ) ) ) ; keyResolverList . add ( new KeyResolver ( new X509CertificateResolver ( ) ) ) ; keyResolverList . add ( new KeyResolver ( new X509SKIResolver ( ) ) ) ; keyResolverList . add ( new KeyResolver ( new RetrievalMethodResolver ( ) ) ) ; keyResolverList . add ( new KeyResolver ( new X509SubjectNameResolver ( ) ) ) ; keyResolverList . add ( new KeyResolver ( new X509IssuerSerialResolver ( ) ) ) ; keyResolverList . add ( new KeyResolver ( new DEREncodedKeyValueResolver ( ) ) ) ; keyResolverList . add ( new KeyResolver ( new KeyInfoReferenceResolver ( ) ) ) ; keyResolverList . add ( new KeyResolver ( new X509DigestResolver ( ) ) ) ; resolverVector . addAll ( keyResolverList ) ; }
target:  This method registers the default resolvers.