--- a/src/java.base/share/classes/javax/security/auth/PrivateCredentialPermission.java	Wed Oct 09 17:38:58 2019 +0100
+++ b/src/java.base/share/classes/javax/security/auth/PrivateCredentialPermission.java	Wed Oct 09 09:57:41 2019 -0700
@@ -119,6 +119,7 @@
      *          The set contains elements of type,
      *          {@code PrivateCredentialPermission.CredOwner}.
      */
+    @SuppressWarnings("serial") // Not statically typed as Serializable
     private Set<Principal> principals;  // ignored - kept around for compatibility
     private transient CredOwner[] credOwners;