question: public JcaX509v3CertificateBuilder ( X509Certificate issuerCert , BigInteger serial , Date notBefore , Date notAfter , X500Principal subject , PublicKey publicKey ) { this ( issuerCert . getSubjectX500Principal ( ) , serial , notBefore , notAfter , subject , publicKey ) ; }
target:  Initialise the builder using the subject from the passed in issuerCert as the issuer, as well as passing through and converting the other objects provided.