A DESCRIPTION OF THE PROBLEM :
sun.security.x509.X509CertImpl.delete("x509.info.validity") nulls out info field instead of calling info.delete("validity").

Look at the lines 744-748, https://github.com/openjdk/jdk/blob/master/src/java.base/share/classes/sun/security/x509/X509CertImpl.java#L744

            if (attr.getSuffix() != null) {
                info = null;
            } else {
                info.delete(attr.getSuffix());
            }

It seems like the if condition should be negated (or "if" branches swapped) in order to do the right thing.

I understand the client is not normally expected to call this code, because X509CertImpl instance is supposed to remain read-only once initialized from the certificate content.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Initialize X509CertImpl by calling:

X509CertImpl x509CertImpl = (X509CertImpl) CertificateFactory.getInstance("X.509").generateCertificate(<certficate-input-stream>);

disable readOnly flag with:

Field readOnlyField = X509CertImpl.class.getDeclaredField("readOnly");
readOnlyField.setAccessible(true);
readOnlyField.set(x509CertImpl, false);

then execute:

x509CertImpl.delete(X509CertImpl.NAME + "." + X509CertImpl.INFO + "." + X509CertInfo.VALIDITY);

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
I expect that "validity" field gets "deleted", i.e. null-ed out.
ACTUAL -
Instead null-ing happens to the "info" field, one level higher in the hierarchy of the qualified name given.

---------- BEGIN SOURCE ----------
import sun.security.x509.X509CertImpl;
import sun.security.x509.X509CertInfo;

import java.io.ByteArrayInputStream;
import java.lang.reflect.Field;
import java.nio.charset.StandardCharsets;
import java.security.cert.CertificateFactory;

public class X509CertImplTest {
    public static void main(String[] args) throws Exception {
        final String cert = "-----BEGIN CERTIFICATE-----\n" +
            "MIIBLjCB1qADAgECAgEBMAoGCCqGSM49BAMCMBIxEDAOBgNVBAMMB2xvY2FsQ0Ew\n" +
            "HhcNMjIwMzEwMjMyMjU2WhcNMjIwMzExMjMyMjU2WjAUMRIwEAYDVQQDDAlsb2Nh\n" +
            "bGhvc3QwWTATBgcqhkjOPQIBBggqhkjOPQMBBwNCAATSJzFRm9VrWVhcvrb6k/ql\n" +
            "PvlhDQdNnUkx9v/LmvoLmM8Wqpw7+805V9ke51P/UbB3UreprwY0SEV18URYY/fM\n" +
            "oxswGTAXBgNVHREBAf8EDTALgglsb2NhbGhvc3QwCgYIKoZIzj0EAwIDRwAwRAIg\n" +
            "aKRZuRQR+JJCLwqyr5Xbww6fHSBJuxk/63nNxx/yJzECICJZEuDo4a0gL6BprdEK\n" +
            "06U7+ookw2vCAy99Qc9p34T4\n" +
            "-----END CERTIFICATE-----\n";

        CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509");
        ByteArrayInputStream inStream = new ByteArrayInputStream(cert.getBytes(StandardCharsets.US_ASCII));
        X509CertImpl x509CertImpl = (X509CertImpl) certificateFactory.generateCertificate(inStream);

        //disable readOnly flag
        Field readOnlyField = X509CertImpl.class.getDeclaredField("readOnly");
        readOnlyField.setAccessible(true);
        readOnlyField.set(x509CertImpl, false);

        //act
        x509CertImpl.delete(X509CertImpl.NAME + "." + X509CertImpl.INFO + "." + X509CertInfo.VALIDITY);

        X509CertInfo info = (X509CertInfo) x509CertImpl.get(X509CertImpl.NAME + "." + X509CertImpl.INFO);
        assert info != null; // assertion fails if assertions are enabled
    }
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
None.

FREQUENCY : always