refactor: finalize vars (planning#2403)

client/src/main/java/dev/fitko/fitconnect/core/crypto/utils/CertUtils.java

@@ -86,8 +86,8 @@ public final class CertUtils {
     public static String getSubjectCNFromCertificate(String pemCertificate) {
         try {
             final X509Certificate certificate = X509CertUtils.parseWithException(pemCertificate);
-            X500Principal principal = certificate.getSubjectX500Principal();
-            X500Name x500Name = new X500Name(principal.getName());
+            final X500Principal principal = certificate.getSubjectX500Principal();
+            final X500Name x500Name = new X500Name(principal.getName());
             final RDN x500NameRDN = x500Name.getRDNs(BCStyle.CN)[0];
             return IETFUtils.valueToString(x500NameRDN.getFirst().getValue());
         } catch (CertificateException e) {