--- a/jdk/src/java.base/share/classes/sun/security/provider/certpath/AdaptableX509CertSelector.java	Tue Nov 10 15:00:25 2015 +0100
+++ b/jdk/src/java.base/share/classes/sun/security/provider/certpath/AdaptableX509CertSelector.java	Thu Nov 12 16:07:14 2015 -0500
@@ -36,9 +36,7 @@
 
 import sun.security.util.Debug;
 import sun.security.util.DerInputStream;
-import sun.security.util.DerOutputStream;
 import sun.security.x509.SerialNumber;
-import sun.security.x509.KeyIdentifier;
 import sun.security.x509.AuthorityKeyIdentifierExtension;
 
 /**
@@ -131,13 +129,7 @@
         serial = null;
 
         if (ext != null) {
-            KeyIdentifier akid = (KeyIdentifier)ext.get(
-                AuthorityKeyIdentifierExtension.KEY_ID);
-            if (akid != null) {
-                DerOutputStream derout = new DerOutputStream();
-                derout.putOctetString(akid.getIdentifier());
-                ski = derout.toByteArray();
-            }
+            ski = ext.getEncodedKeyIdentifier();
             SerialNumber asn = (SerialNumber)ext.get(
                 AuthorityKeyIdentifierExtension.SERIAL_NUMBER);
             if (asn != null) {

--- a/jdk/src/java.base/share/classes/sun/security/provider/certpath/DistributionPointFetcher.java	Tue Nov 10 15:00:25 2015 +0100
+++ b/jdk/src/java.base/share/classes/sun/security/provider/certpath/DistributionPointFetcher.java	Thu Nov 12 16:07:14 2015 -0500
@@ -33,7 +33,6 @@
 import java.util.*;
 
 import sun.security.util.Debug;
-import sun.security.util.DerOutputStream;
 import static sun.security.x509.PKIXExtensions.*;
 import sun.security.x509.*;
 
@@ -607,12 +606,9 @@
             AuthorityKeyIdentifierExtension akidext =
                                             crlImpl.getAuthKeyIdExtension();
             if (akidext != null) {
-                KeyIdentifier akid = (KeyIdentifier)akidext.get(
-                        AuthorityKeyIdentifierExtension.KEY_ID);
-                if (akid != null) {
-                    DerOutputStream derout = new DerOutputStream();
-                    derout.putOctetString(akid.getIdentifier());
-                    certSel.setSubjectKeyIdentifier(derout.toByteArray());
+                byte[] kid = akidext.getEncodedKeyIdentifier();
+                if (kid != null) {
+                    certSel.setSubjectKeyIdentifier(kid);
                 }
 
                 SerialNumber asn = (SerialNumber)akidext.get(

--- a/jdk/src/java.base/share/classes/sun/security/provider/certpath/ForwardBuilder.java	Tue Nov 10 15:00:25 2015 +0100
+++ b/jdk/src/java.base/share/classes/sun/security/provider/certpath/ForwardBuilder.java	Thu Nov 12 16:07:14 2015 -0500
@@ -46,9 +46,10 @@
 import sun.security.util.Debug;
 import sun.security.x509.AccessDescription;
 import sun.security.x509.AuthorityInfoAccessExtension;
+import sun.security.x509.AuthorityKeyIdentifierExtension;
 import static sun.security.x509.PKIXExtensions.*;
 import sun.security.x509.X500Name;
-import sun.security.x509.AuthorityKeyIdentifierExtension;
+import sun.security.x509.X509CertImpl;
 
 /**
  * This class represents a forward builder, which is able to retrieve
@@ -69,7 +70,6 @@
     private AdaptableX509CertSelector caSelector;
     private X509CertSelector caTargetSelector;
     TrustAnchor trustAnchor;
-    private Comparator<X509Certificate> comparator;
     private boolean searchAllCertStores = true;
 
     /**
@@ -93,7 +93,6 @@
                 trustedSubjectDNs.add(anchor.getCA());
             }
         }
-        comparator = new PKIXCertComparator(trustedSubjectDNs);
         this.searchAllCertStores = searchAllCertStores;
     }
 
@@ -122,6 +121,8 @@
          * As each cert is added, it is sorted based on the PKIXCertComparator
          * algorithm.
          */
+        Comparator<X509Certificate> comparator =
+            new PKIXCertComparator(trustedSubjectDNs, currState.cert);
         Set<X509Certificate> certs = new TreeSet<>(comparator);
 
         /*
@@ -265,14 +266,6 @@
                 (caSelector, currentState.subjectNamesTraversed);
 
             /*
-             * Facilitate certification path construction with authority
-             * key identifier and subject key identifier.
-             */
-            AuthorityKeyIdentifierExtension akidext =
-                    currentState.cert.getAuthorityKeyIdentifierExtension();
-            caSelector.setSkiAndSerialNumber(akidext);
-
-            /*
              * check the validity period
              */
             caSelector.setValidityPeriod(currentState.cert.getNotBefore(),
@@ -404,41 +397,68 @@
      *
      * Preference order for current cert:
      *
-     * 1) Issuer matches a trusted subject
+     * 1) The key identifier of an AKID extension (if present) in the
+     *    previous certificate matches the key identifier in the SKID extension
+     *
+     * 2) Issuer matches a trusted subject
      *    Issuer: ou=D,ou=C,o=B,c=A
      *
-     * 2) Issuer is a descendant of a trusted subject (in order of
+     * 3) Issuer is a descendant of a trusted subject (in order of
      *    number of links to the trusted subject)
      *    a) Issuer: ou=E,ou=D,ou=C,o=B,c=A        [links=1]
      *    b) Issuer: ou=F,ou=E,ou=D,ou=C,ou=B,c=A  [links=2]
      *
-     * 3) Issuer is an ancestor of a trusted subject (in order of number of
+     * 4) Issuer is an ancestor of a trusted subject (in order of number of
      *    links to the trusted subject)
      *    a) Issuer: ou=C,o=B,c=A [links=1]
      *    b) Issuer: o=B,c=A      [links=2]
      *
-     * 4) Issuer is in the same namespace as a trusted subject (in order of
+     * 5) Issuer is in the same namespace as a trusted subject (in order of
      *    number of links to the trusted subject)
      *    a) Issuer: ou=G,ou=C,o=B,c=A  [links=2]
      *    b) Issuer: ou=H,o=B,c=A       [links=3]
      *
-     * 5) Issuer is an ancestor of certificate subject (in order of number
+     * 6) Issuer is an ancestor of certificate subject (in order of number
      *    of links to the certificate subject)
      *    a) Issuer:  ou=K,o=J,c=A
      *       Subject: ou=L,ou=K,o=J,c=A
      *    b) Issuer:  o=J,c=A
      *       Subject: ou=L,ou=K,0=J,c=A
      *
-     * 6) Any other certificates
+     * 7) Any other certificates
      */
     static class PKIXCertComparator implements Comparator<X509Certificate> {
 
         static final String METHOD_NME = "PKIXCertComparator.compare()";
 
         private final Set<X500Principal> trustedSubjectDNs;
+        private final X509CertSelector certSkidSelector;
 
-        PKIXCertComparator(Set<X500Principal> trustedSubjectDNs) {
+        PKIXCertComparator(Set<X500Principal> trustedSubjectDNs,
+                           X509CertImpl previousCert) throws IOException {
             this.trustedSubjectDNs = trustedSubjectDNs;
+            this.certSkidSelector = getSelector(previousCert);
+        }
+
+        /**
+         * Returns an X509CertSelector for matching on the authority key
+         * identifier, or null if not applicable.
+         */
+        private X509CertSelector getSelector(X509CertImpl previousCert)
+            throws IOException {
+            if (previousCert != null) {
+                AuthorityKeyIdentifierExtension akidExt =
+                    previousCert.getAuthorityKeyIdentifierExtension();
+                if (akidExt != null) {
+                    byte[] skid = akidExt.getEncodedKeyIdentifier();
+                    if (skid != null) {
+                        X509CertSelector selector = new X509CertSelector();
+                        selector.setSubjectKeyIdentifier(skid);
+                        return selector;
+                    }
+                }
+            }
+            return null;
         }
 
         /**
@@ -462,6 +482,16 @@
             // if certs are the same, return 0
             if (oCert1.equals(oCert2)) return 0;
 
+            // If akid/skid match then it is preferable
+            if (certSkidSelector != null) {
+                if (certSkidSelector.match(oCert1)) {
+                    return -1;
+                }
+                if (certSkidSelector.match(oCert2)) {
+                    return 1;
+                }
+            }
+
             X500Principal cIssuer1 = oCert1.getIssuerX500Principal();
             X500Principal cIssuer2 = oCert2.getIssuerX500Principal();
             X500Name cIssuer1Name = X500Name.asX500Name(cIssuer1);

--- a/jdk/src/java.base/share/classes/sun/security/x509/AuthorityKeyIdentifierExtension.java	Tue Nov 10 15:00:25 2015 +0100
+++ b/jdk/src/java.base/share/classes/sun/security/x509/AuthorityKeyIdentifierExtension.java	Thu Nov 12 16:07:14 2015 -0500
@@ -310,4 +310,16 @@
     public String getName() {
         return (NAME);
     }
+
+    /**
+     * Return the encoded key identifier, or null if not specified.
+     */
+    public byte[] getEncodedKeyIdentifier() throws IOException {
+        if (id != null) {
+            DerOutputStream derOut = new DerOutputStream();
+            id.encode(derOut);
+            return derOut.toByteArray();
+        }
+        return null;
+    }
 }