in alloydb-jdbc-connector/src/main/java/com/google/cloud/alloydb/DefaultConnectionInfoRepository.java [158:162]
private X509Certificate parseCertificate(ByteString cert) throws CertificateException {
ByteArrayInputStream certStream = new ByteArrayInputStream(cert.toByteArray());
CertificateFactory x509CertificateFactory = CertificateFactory.getInstance(X_509);
return (X509Certificate) x509CertificateFactory.generateCertificate(certStream);
}