diff -r cb883ad42653 -r 3c6da11f3a96 jdk/test/sun/security/krb5/auto/CommMatcher.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/sun/security/krb5/auto/CommMatcher.java	Wed Aug 17 10:08:18 2016 +0800
@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * Matches the krb5 debug output:
+ * >>> KDCCommunication: kdc=host UDP:11555, timeout=100,Attempt =1, #bytes=138
+ *
+ * Example:
+ *   CommMatcher cm = new CommMatcher();
+ *   cm.addPort(12345).addPort(23456);
+ *   for (String line : debugOutput) {
+ *       if (cm.match(line)) {
+ *           println("KDC: %c, %s, Timeout: %d\n",
+ *              cm.kdc(), cm.protocol(), cm.timeout());
+ *       }
+ *   }
+ */
+public class CommMatcher {
+
+    static final Pattern re = Pattern.compile(
+            ">>> KDCCommunication: kdc=\\S+ (TCP|UDP):(\\d+), " +
+                    "timeout=(\\d+),Attempt\\s*=(\\d+)");
+
+    List<Integer> kdcPorts = new ArrayList<>();
+    Matcher matcher;
+
+    /**
+     * Add KDC ports one by one. The 1st KDC will be 'a' in {@link #kdc()},
+     * 2nd is 'b', etc, etc.
+     */
+    public CommMatcher addPort(int port) {
+        if (port > 0) {
+            kdcPorts.add(port);
+        } else {
+            kdcPorts.clear();
+        }
+        return this;
+    }
+
+    public boolean match(String line) {
+        matcher = re.matcher(line);
+        return matcher.find();
+    }
+
+    public String protocol() {
+        return matcher.group(1);
+    }
+
+    public char kdc() {
+        int port = Integer.parseInt(matcher.group(2));
+        return (char)(kdcPorts.indexOf(port) + 'a');
+    }
+
+    public int timeout() {
+        return BadKdc.toSymbolicSec(Integer.parseInt(matcher.group(3)));
+    }
+
+    public int attempt() {
+        return Integer.parseInt(matcher.group(4));
+    }
+}