Yahoo sets up mac wireless networks such that the local hostname points to an

ip which does not resolve. This works around that problem by finding a resolvable
address (while still falling back to localhost if we only get ipv6 addresses,
as that causes other problems in docker containers).

10 files changed, 294 insertions, 320 deletions

diff --git a/jrt/src/com/yahoo/jrt/Acceptor.java b/jrt/src/com/yahoo/jrt/Acceptor.java
index 05a7591ab74..7316f8c620b 100644
--- a/jrt/src/com/yahoo/jrt/Acceptor.java
+++ b/jrt/src/com/yahoo/jrt/Acceptor.java
@@ -13,7 +13,7 @@ import java.util.logging.Logger;
  * transport thread. To create an acceptor you need to invoke the
  * {@link Supervisor#listen listen} method in the {@link Supervisor}
  * class.
- **/
+ */
 public class Acceptor {
 
     private class Run implements Runnable {
@@ -34,15 +34,12 @@ public class Acceptor {
 
     private ServerSocketChannel serverChannel;
 
-    Acceptor(Transport parent, Supervisor owner,
-             Spec spec) throws ListenFailedException {
-
+    Acceptor(Transport parent, Supervisor owner, Spec spec) throws ListenFailedException {
         this.parent = parent;
         this.owner  = owner;
 
-        if (spec.malformed()) {
-            throw new ListenFailedException("Malformed spec");
-        }
+        if (spec.malformed())
+            throw new ListenFailedException("Malformed spec '" + spec + "'");
 
         try {
             serverChannel = ServerSocketChannel.open();
@@ -55,7 +52,7 @@ public class Acceptor {
             if (serverChannel != null) {
                 try { serverChannel.socket().close(); } catch (Exception x) {}
             }
-            throw new ListenFailedException("Listen failed", e);
+            throw new ListenFailedException("Failed to listen to " + spec, e);
         }
 
         thread.setDaemon(true);
@@ -84,7 +81,7 @@ public class Acceptor {
      * @return listening spec, or null if not listening.
      **/
     public Spec spec() {
-        if (!serverChannel.isOpen()) {
+        if ( ! serverChannel.isOpen()) {
             return null;
         }
         return new Spec(serverChannel.socket().getInetAddress().getHostName(),
@@ -94,8 +91,7 @@ public class Acceptor {
     private void run() {
         while (serverChannel.isOpen()) {
             try {
-                parent.addConnection(new Connection(parent, owner,
-                                                    serverChannel.accept()));
+                parent.addConnection(new Connection(parent, owner, serverChannel.accept()));
                 parent.sync();
             } catch (java.nio.channels.ClosedChannelException x) {
             } catch (Exception e) {
diff --git a/jrt/src/com/yahoo/jrt/Connection.java b/jrt/src/com/yahoo/jrt/Connection.java
index 7affa875cd6..52964726eb7 100644
--- a/jrt/src/com/yahoo/jrt/Connection.java
+++ b/jrt/src/com/yahoo/jrt/Connection.java
@@ -1,7 +1,6 @@
 // Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.jrt;
 
-
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.nio.channels.SelectionKey;
@@ -35,10 +34,8 @@ class Connection extends Target {
     private Buffer        output     = new Buffer(WRITE_SIZE * 2);
     private int           maxInputSize  = 64*1024;
     private int           maxOutputSize = 64*1024;
-    private Map<Integer, ReplyHandler> replyMap
-        = new HashMap<Integer, ReplyHandler>();
-    private Map<TargetWatcher, TargetWatcher> watchers
-        = new IdentityHashMap<TargetWatcher, TargetWatcher>();
+    private Map<Integer, ReplyHandler> replyMap = new HashMap<>();
+    private Map<TargetWatcher, TargetWatcher> watchers = new IdentityHashMap<>();
     private int           activeReqs = 0;
     private int           writeWork  = 0;
     private Transport     parent;
@@ -52,8 +49,7 @@ class Connection extends Target {
 
     private void setState(int state) {
         if (state <= this.state) {
-            log.log(Level.WARNING, "Bogus state transition: "
-                    + this.state + "->" + state);
+            log.log(Level.WARNING, "Bogus state transition: " + this.state + "->" + state);
             return;
         }
         boolean live = (this.state == INITIAL && state == CONNECTED);
@@ -95,8 +91,7 @@ class Connection extends Target {
         owner.sessionInit(this);
     }
 
-    public Connection(Transport parent, Supervisor owner,
-                      Spec spec, Object context) {
+    public Connection(Transport parent, Supervisor owner, Spec spec, Object context) {
         super(context);
         this.parent = parent;
         this.owner = owner;
@@ -400,6 +395,6 @@ class Connection extends Target {
         if (channel != null) {
             return "Connection { " + channel.socket() + " }";
         }
-        return "Connection { no socket }";
+        return "Connection { no socket, spec " + spec + " }";
     }
 }
diff --git a/jrt/src/com/yahoo/jrt/Connector.java b/jrt/src/com/yahoo/jrt/Connector.java
index fa43710b1f6..6778e047a8b 100644
--- a/jrt/src/com/yahoo/jrt/Connector.java
+++ b/jrt/src/com/yahoo/jrt/Connector.java
@@ -27,7 +27,7 @@ class Connector {
     }
 
     public void connectLater(Connection c) {
-        if (!connectQueue.enqueue(c)) {
+        if ( ! connectQueue.enqueue(c)) {
             parent.addConnection(c);
         }
     }
diff --git a/jrt/src/com/yahoo/jrt/Request.java b/jrt/src/com/yahoo/jrt/Request.java
index 99d7df8657e..4786124e56b 100644
--- a/jrt/src/com/yahoo/jrt/Request.java
+++ b/jrt/src/com/yahoo/jrt/Request.java
@@ -14,7 +14,7 @@ package com.yahoo.jrt;
  * client/server roles are independent of connection client/server
  * roles, since invocations can be performed both ways across a {@link
  * Target}.
- **/
+ */
 public class Request
 {
     private String  methodName;
@@ -242,8 +242,7 @@ public class Request
         if (returnValues.satisfies(returnTypes)) {
             return true;
         }
-        setError(ErrorCode.WRONG_RETURN,
-                 "checkReturnValues: Wrong return values");
+        setError(ErrorCode.WRONG_RETURN, "checkReturnValues: Wrong return values");
         return false;
     }
 
diff --git a/jrt/src/com/yahoo/jrt/Spec.java b/jrt/src/com/yahoo/jrt/Spec.java
index 7ed0aa69920..4c1f07b98a2 100644
--- a/jrt/src/com/yahoo/jrt/Spec.java
+++ b/jrt/src/com/yahoo/jrt/Spec.java
@@ -2,6 +2,8 @@
 package com.yahoo.jrt;
 
 
+import com.yahoo.net.HostName;
+
 import java.net.SocketAddress;
 import java.net.InetSocketAddress;
 
@@ -9,9 +11,9 @@ import java.net.InetSocketAddress;
 /**
  * A Spec is a network address used for either listening or
  * connecting.
- **/
-public class Spec
-{
+ */
+public class Spec {
+
     private SocketAddress address;
     private String        host;
     private int           port;
@@ -24,11 +26,11 @@ public class Spec
      *
      * @param spec input string to be parsed
      * @see #malformed
-     **/
+     */
     public Spec(String spec) {
         if (spec.startsWith("tcp/")) {
             int sep = spec.indexOf(':');
-            String portStr = null;
+            String portStr;
             if (sep == -1) {
                 portStr = spec.substring(4);
             } else {
@@ -52,7 +54,7 @@ public class Spec
      *
      * @param host host name
      * @param port port number
-     **/
+     */
     public Spec(String host, int port) {
         this.host = host;
         this.port = port;
@@ -62,7 +64,7 @@ public class Spec
      * Create a Spec from a port number.
      *
      * @param port port number
-     **/
+     */
     public Spec(int port) {
         this.port = port;
     }
@@ -71,7 +73,7 @@ public class Spec
      * Obtain the host name of this address
      *
      * @return host name
-     **/
+     */
     public String host() {
         return host;
     }
@@ -80,7 +82,7 @@ public class Spec
      * Obtain the port number if this address
      *
      * @return port number
-     **/
+     */
     public int port() {
         return port;
     }
@@ -90,7 +92,7 @@ public class Spec
      * you whether that string was malformed.
      *
      * @return true if this address is malformed
-     **/
+     */
     public boolean malformed() {
         return malformed;
     }
@@ -100,7 +102,7 @@ public class Spec
      * malformed, this method will return null.
      *
      * @return socket address
-     **/
+     */
     SocketAddress address() {
         if (malformed) {
             return null;
@@ -114,13 +116,13 @@ public class Spec
         }
         return address;
     }
-
+    
     /**
      * Obtain a string representation of this address. The return
      * value from this method may be used to create a new Spec.
      *
      * @return string representation of this address
-     **/
+     */
     public String toString() {
         if (malformed) {
             return "MALFORMED";
@@ -130,4 +132,5 @@ public class Spec
         }
         return "tcp/" + host + ":" + port;
     }
+
 }
diff --git a/jrt/src/com/yahoo/jrt/Transport.java b/jrt/src/com/yahoo/jrt/Transport.java
index 85bfed79732..6a9a978fb77 100644
--- a/jrt/src/com/yahoo/jrt/Transport.java
+++ b/jrt/src/com/yahoo/jrt/Transport.java
@@ -229,9 +229,8 @@ public class Transport {
      * @param context application context for the new connection
      * @param sync perform a synchronous connect in the calling thread
      *             if this flag is set
-     **/
-    Connection connect(Supervisor owner, Spec spec,
-                       Object context, boolean sync) {
+     */
+    Connection connect(Supervisor owner, Spec spec, Object context, boolean sync) {
         Connection conn = new Connection(this, owner, spec, context);
         if (sync) {
             addConnection(conn.connect());
diff --git a/jrt/src/com/yahoo/jrt/slobrok/api/IMirror.java b/jrt/src/com/yahoo/jrt/slobrok/api/IMirror.java
index 3662e6ad5b9..421590e72ce 100644
--- a/jrt/src/com/yahoo/jrt/slobrok/api/IMirror.java
+++ b/jrt/src/com/yahoo/jrt/slobrok/api/IMirror.java
@@ -4,8 +4,8 @@ package com.yahoo.jrt.slobrok.api;
 /**
  * Defines an interface for the name server lookup.
  *
- * @author <a href="mailto:simon@yahoo-inc.com">Simon Thoresen</a>
- **/
+ * @author Simon Thoresen
+ */
 public interface IMirror {
 
     /**
@@ -21,7 +21,7 @@ public interface IMirror {
      * @return a list of all matching services, with corresponding connect specs
      * @param pattern The pattern used for matching
      **/
-    public Mirror.Entry[] lookup(String pattern);
+    Mirror.Entry[] lookup(String pattern);
 
     /**
      * Obtain the number of updates seen by this mirror. The value may wrap, but will never become 0 again. This can be
@@ -30,5 +30,6 @@ public interface IMirror {
      *
      * @return number of slobrok updates seen
      **/
-    public int updates();
+    int updates();
+
 }
diff --git a/jrt/src/com/yahoo/jrt/slobrok/api/Mirror.java b/jrt/src/com/yahoo/jrt/slobrok/api/Mirror.java
index 5e62cb61b76..81ec51e2b9e 100644
--- a/jrt/src/com/yahoo/jrt/slobrok/api/Mirror.java
+++ b/jrt/src/com/yahoo/jrt/slobrok/api/Mirror.java
@@ -1,16 +1,14 @@
 // Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.jrt.slobrok.api;
 
-
 import com.yahoo.jrt.*;
 
-import java.util.Arrays;
-import java.util.Random;
 import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Map;
 import java.util.logging.Logger;
 import java.util.logging.Level;
 
-
 /**
  * A Mirror object is used to keep track of the services registered
  * with a slobrok cluster.
@@ -18,57 +16,19 @@ import java.util.logging.Level;
  * Updates to the service repository are fetched in the
  * background. Lookups against this object is done using an internal
  * mirror of the service repository.
- **/
+ */
 public class Mirror implements IMirror {
 
     private static Logger log = Logger.getLogger(Mirror.class.getName());
 
-    /**
-     * An Entry contains the name and connection spec for a single
-     * service.
-     **/
-    public static final class Entry implements Comparable<Entry> {
-        private final String name;
-        private final String spec;
-        private final char [] nameArray;
-
-        public Entry(String name, String spec) {
-            this.name = name;
-            this.spec = spec;
-            this.nameArray = name.toCharArray();
-        }
-
-        public boolean equals(Object rhs) {
-            if (rhs == null || !(rhs instanceof Entry)) {
-                return false;
-            }
-            Entry e = (Entry) rhs;
-            return (name.equals(e.name) && spec.equals(e.spec));
-        }
-
-        public int hashCode() {
-            return (name.hashCode() + spec.hashCode());
-        }
-
-        public int compareTo(Entry b) {
-            int diff = name.compareTo(b.name);
-            return diff != 0
-                       ? diff
-                       : spec.compareTo(b.spec);
-        }
-        char [] getNameArray() { return nameArray; }
-        public String getName() { return name; }
-        public String getSpec() { return spec; }
-    }
-
     private Supervisor        orb;
     private SlobrokList       slobroks;
     private String            currSlobrok;
     private BackOffPolicy     backOff;
     private volatile int      updates    = 0;
-    private boolean           reqDone    = false;
+    private boolean requestDone = false;
     private volatile Entry[]  specs      = new Entry[0];
-    private int               specsGen   = 0;
+    private int specsGeneration = 0;
     private Task              updateTask = null;
     private RequestWaiter     reqWait    = null;
     private Target            target     = null;
@@ -87,11 +47,11 @@ public class Mirror implements IMirror {
         this.slobroks = slobroks;
         this.backOff = bop;
         updateTask = orb.transport().createTask(new Runnable() {
-                public void run() { handleUpdate(); }
+                public void run() { checkForUpdate(); }
             });
         reqWait = new RequestWaiter() {
                 public void handleRequestDone(Request req) {
-                    reqDone = true;
+                    requestDone = true;
                     updateTask.scheduleNow();
                 }
             };
@@ -104,7 +64,7 @@ public class Mirror implements IMirror {
      *
      * @param orb the Supervisor to use
      * @param slobroks slobrok connect spec list
-     **/
+     */
     public Mirror(Supervisor orb, SlobrokList slobroks) {
         this(orb, slobroks, new BackOff());
     }
@@ -112,7 +72,7 @@ public class Mirror implements IMirror {
     /**
      * Shut down the Mirror. This will close any open connections and
      * stop the regular mirror updates.
-     **/
+     */
     public void shutdown() {
         updateTask.kill();
         orb.transport().perform(new Runnable() {
@@ -122,12 +82,11 @@ public class Mirror implements IMirror {
 
     @Override
     public Entry[] lookup(String pattern) {
-        ArrayList<Entry> found = new ArrayList<Entry>();
-        Entry [] e = specs;
-        char [] p = pattern.toCharArray();
-        for (int i = 0; i < e.length; i++) {
-            if (match(e[i].getNameArray(), p)) {
-                found.add(e[i]);
+        ArrayList<Entry> found = new ArrayList<>();
+        char[] p = pattern.toCharArray();
+        for (Entry specEntry : specs) {
+            if (match(specEntry.getNameArray(), p)) {
+                found.add(specEntry);
             }
         }
         return found.toArray(new Entry[found.size()]);
@@ -145,7 +104,7 @@ public class Mirror implements IMirror {
      * (or if it never does, time out and tell the user there was no answer from any Service Location Broker).
      *
      * @return true if the MirrorAPI object has asked for updates from a Slobrok and got any answer back
-     **/
+     */
     public boolean ready() {
         return (updates != 0);
     }
@@ -167,7 +126,7 @@ public class Mirror implements IMirror {
      * @return true if the name matches the pattern
      * @param name the name
      * @param pattern the pattern
-     **/
+     */
     static boolean match(char [] name, char [] pattern) {
         int ni = 0;
         int pi = 0;
@@ -197,95 +156,58 @@ public class Mirror implements IMirror {
 
     /**
      * Invoked by the update task.
-     **/
-    private void handleUpdate() {
-        if (reqDone) {
-            reqDone = false;
-
-            if (req.errorCode() == ErrorCode.NONE &&
-                req.returnValues().satisfies("SSi") &&
-                req.returnValues().get(0).count() == req.returnValues().get(1).count())
-            {
-                Values answer = req.returnValues();
-
-                if (specsGen != answer.get(2).asInt32()) {
-
-                    int      numNames = answer.get(0).count();
-                    String[]        n = answer.get(0).asStringArray();
-                    String[]        s = answer.get(1).asStringArray();
-                    Entry[]  newSpecs = new Entry[numNames];
-
-                    for (int idx = 0; idx < numNames; idx++) {
-                        newSpecs[idx] = new Entry(n[idx], s[idx]);
-                    }
-
-                    specs = newSpecs;
-
-                    specsGen = answer.get(2).asInt32();
-                    int u = (updates + 1);
-                    if (u == 0) {
-                        u++;
-                    }
-                    updates = u;
+     */
+    private void checkForUpdate() {
+        if (requestDone) {
+            handleUpdate();
+            requestDone = false;
+            return;
+        }
+
+        if (target != null && ! slobroks.contains(currSlobrok)) {
+            target.close();
+            target = null;
+        }
+        if (target == null) {
+            currSlobrok = slobroks.nextSlobrokSpec();
+            if (currSlobrok == null) {
+                double delay = backOff.get();
+                updateTask.schedule(delay);
+                if (backOff.shouldWarn(delay)) {
+                    log.log(Level.INFO, "no location brokers available "
+                            + "(retry in " + delay + " seconds) for: " + slobroks);
                 }
-                backOff.reset();
-                updateTask.schedule(0.1); // be nice
-                return;
-            }
-            if (!req.checkReturnTypes("iSSSi")
-                || (req.returnValues().get(2).count() !=
-                    req.returnValues().get(3).count()))
-            {
-                target.close();
-                target = null;
-                updateTask.scheduleNow(); // try next slobrok
                 return;
             }
+            target = orb.connect(new Spec(currSlobrok));
+            specsGeneration = 0;
+        }
+        req = new Request("slobrok.incremental.fetch");
+        req.parameters().add(new Int32Value(specsGeneration)); // gencnt
+        req.parameters().add(new Int32Value(5000));     // mstimeout
+        target.invokeAsync(req, 40.0, reqWait);
+    }
+    
+    private void handleUpdate() {
+        if (req.errorCode() == ErrorCode.NONE &&
+            req.returnValues().satisfies("SSi") &&
+            req.returnValues().get(0).count() == req.returnValues().get(1).count())
+        {
+            Values answer = req.returnValues();
 
+            if (specsGeneration != answer.get(2).asInt32()) {
 
-            Values answer = req.returnValues();
+                int      numNames = answer.get(0).count();
+                String[]        n = answer.get(0).asStringArray();
+                String[]        s = answer.get(1).asStringArray();
+                Entry[]  newSpecs = new Entry[numNames];
 
-            int diffFrom = answer.get(0).asInt32();
-            int diffTo   = answer.get(4).asInt32();
-
-            if (specsGen != diffTo) {
-
-                int      nRemoves = answer.get(1).count();
-                String[]        r = answer.get(1).asStringArray();
-
-                int      numNames = answer.get(2).count();
-                String[]        n = answer.get(2).asStringArray();
-                String[]        s = answer.get(3).asStringArray();
-
-
-                Entry[]  newSpecs;
-                if (diffFrom == 0) {
-                    newSpecs = new Entry[numNames];
-
-                    for (int idx = 0; idx < numNames; idx++) {
-                        newSpecs[idx] = new Entry(n[idx], s[idx]);
-                    }
-                } else {
-                    java.util.HashMap<String, Entry> map = new java.util.HashMap<String, Entry>();
-                    for (Entry e : specs) {
-                        map.put(e.getName(), e);
-                    }
-                    for (String rem : r) {
-                        map.remove(rem);
-                    }
-                    for (int idx = 0; idx < numNames; idx++) {
-                        map.put(n[idx], new Entry(n[idx], s[idx]));
-                    }
-                    newSpecs = new Entry[map.size()];
-                    int idx = 0;
-                    for (Entry e : map.values()) {
-                        newSpecs[idx++] = e;
-                    }
+                for (int idx = 0; idx < numNames; idx++) {
+                    newSpecs[idx] = new Entry(n[idx], s[idx]);
                 }
-
                 specs = newSpecs;
 
-                specsGen = diffTo;
+                specsGeneration = answer.get(2).asInt32();
                 int u = (updates + 1);
                 if (u == 0) {
                     u++;
@@ -296,34 +218,72 @@ public class Mirror implements IMirror {
             updateTask.schedule(0.1); // be nice
             return;
         }
-        if (target != null && ! slobroks.contains(currSlobrok)) {
+        if (!req.checkReturnTypes("iSSSi")
+            || (req.returnValues().get(2).count() !=
+                req.returnValues().get(3).count()))
+        {
             target.close();
             target = null;
+            updateTask.scheduleNow(); // try next slobrok
+            return;
         }
-        if (target == null) {
-            currSlobrok = slobroks.nextSlobrokSpec();
-            if (currSlobrok == null) {
-                double delay = backOff.get();
-                updateTask.schedule(delay);
-                if (backOff.shouldWarn(delay)) {
-                    log.log(Level.INFO, "no location brokers available "
-                            + "(retry in " + delay + " seconds) for: " + slobroks);
+
+
+        Values answer = req.returnValues();
+
+        int diffFromGeneration = answer.get(0).asInt32();
+        int diffToGeneration   = answer.get(4).asInt32();
+        if (specsGeneration != diffToGeneration) {
+
+            int      nRemoves = answer.get(1).count();
+            String[]        r = answer.get(1).asStringArray();
+
+            int      numNames = answer.get(2).count();
+            String[]        n = answer.get(2).asStringArray();
+            String[]        s = answer.get(3).asStringArray();
+
+            Entry[]  newSpecs;
+            if (diffFromGeneration == 0) {
+                newSpecs = new Entry[numNames];
+
+                for (int idx = 0; idx < numNames; idx++) {
+                    newSpecs[idx] = new Entry(n[idx], s[idx]);
+                }
+            } else {
+                Map<String, Entry> map = new HashMap<>();
+                for (Entry e : specs) {
+                    map.put(e.getName(), e);
+                }
+                for (String rem : r) {
+                    map.remove(rem);
+                }
+                for (int idx = 0; idx < numNames; idx++) {
+                    map.put(n[idx], new Entry(n[idx], s[idx]));
+                }
+                newSpecs = new Entry[map.size()];
+                int idx = 0;
+                for (Entry e : map.values()) {
+                    newSpecs[idx++] = e;
                 }
-                return;
             }
-            target = orb.connect(new Spec(currSlobrok));
-            specsGen = 0;
+
+            specs = newSpecs;
+
+            specsGeneration = diffToGeneration;
+            int u = (updates + 1);
+            if (u == 0) {
+                u++;
+            }
+            updates = u;
         }
-        req = new Request("slobrok.incremental.fetch");
-        req.parameters().add(new Int32Value(specsGen)); // gencnt
-        req.parameters().add(new Int32Value(5000));     // mstimeout
-        target.invokeAsync(req, 40.0, reqWait);
+        backOff.reset();
+        updateTask.schedule(0.1); // be nice
     }
 
     /**
      * Invoked from the transport thread, requested by the shutdown
      * method.
-     **/
+     */
     private void handleShutdown() {
         if (req != null) {
             req.abort();
@@ -334,4 +294,44 @@ public class Mirror implements IMirror {
             target = null;
         }
     }
+
+    /**
+     * An Entry contains the name and connection spec for a single
+     * service.
+     */
+    public static final class Entry implements Comparable<Entry> {
+
+        private final String name;
+        private final String spec;
+        private final char [] nameArray;
+
+        public Entry(String name, String spec) {
+            this.name = name;
+            this.spec = spec;
+            this.nameArray = name.toCharArray();
+        }
+
+        public boolean equals(Object rhs) {
+            if (rhs == null || !(rhs instanceof Entry)) {
+                return false;
+            }
+            Entry e = (Entry) rhs;
+            return (name.equals(e.name) && spec.equals(e.spec));
+        }
+
+        public int hashCode() {
+            return (name.hashCode() + spec.hashCode());
+        }
+
+        public int compareTo(Entry b) {
+            int diff = name.compareTo(b.name);
+            return diff != 0 ? diff : spec.compareTo(b.spec);
+        }
+
+        char [] getNameArray() { return nameArray; }
+        public String getName() { return name; }
+        public String getSpec() { return spec; }
+
+    }
+
 }
diff --git a/jrt/src/com/yahoo/jrt/slobrok/api/Register.java b/jrt/src/com/yahoo/jrt/slobrok/api/Register.java
index 84720501ff8..d1ea7a7f1fa 100644
--- a/jrt/src/com/yahoo/jrt/slobrok/api/Register.java
+++ b/jrt/src/com/yahoo/jrt/slobrok/api/Register.java
@@ -1,22 +1,21 @@
 // Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.jrt.slobrok.api;
 
-
 import com.yahoo.jrt.*;
 import java.util.ArrayList;
+import java.util.List;
 import java.util.Random;
 import java.util.logging.Logger;
 import java.util.logging.Level;
 
-
 /**
  * A Register object is used to register and unregister services with
  * a slobrok cluster.
  *
  * The register/unregister operations performed against this object
- * are stored in a todo list that will be performed asynchronously
+ * are stored in a to-do list that will be performed asynchronously
  * against the slobrok cluster as soon as possible.
- **/
+ */
 public class Register {
 
     private static Logger log = Logger.getLogger(Register.class.getName());
@@ -27,9 +26,9 @@ public class Register {
     private String        mySpec;
     private BackOffPolicy backOff;
     private boolean       reqDone    = false;
-    private ArrayList<String>     names      = new ArrayList<String>();
-    private ArrayList<String>     pending    = new ArrayList<String>();
-    private ArrayList<String>     unreg      = new ArrayList<String>();
+    private List<String>     names      = new ArrayList<>();
+    private List<String> pending    = new ArrayList<>();
+    private List<String>     unreg      = new ArrayList<>();
     private Task          updateTask = null;
     private RequestWaiter reqWait    = null;
     private Target        target     = null;
@@ -39,9 +38,9 @@ public class Register {
 
     /**
      * Remove all instances of name from list.
-     **/
-    private void discard(ArrayList<String> list, String name) {
-        ArrayList<String> tmp = new ArrayList<String>();
+     */
+    private void discard(List<String> list, String name) {
+        List<String> tmp = new ArrayList<>();
         tmp.add(name);
         list.removeAll(tmp);
     }
@@ -54,7 +53,7 @@ public class Register {
      * @param slobroks slobrok connect spec list
      * @param spec the Spec representing hostname and port for this host
      * @param bop custom backoff policy, mostly useful for testing
-     **/
+     */
     public Register(Supervisor orb, SlobrokList slobroks, Spec spec, BackOffPolicy bop) {
         this.orb = orb;
         this.slobroks = slobroks;
@@ -98,7 +97,7 @@ public class Register {
      * @param orb the Supervisor to use
      * @param slobroks slobrok connect spec list
      * @param spec the Spec representing hostname and port for this host
-     **/
+     */
     public Register(Supervisor orb, SlobrokList slobroks, Spec spec) {
         this(orb, slobroks, spec, new BackOff());
     }
@@ -111,9 +110,8 @@ public class Register {
      * @param slobroks slobrok connect spec list
      * @param myHost the hostname of this host
      * @param myPort the port number we are listening to
-     **/
-    public Register(Supervisor orb, SlobrokList slobroks,
-                    String myHost, int myPort) {
+     */
+    public Register(Supervisor orb, SlobrokList slobroks, String myHost, int myPort) {
         this(orb, slobroks, new Spec(myHost, myPort));
     }
 
@@ -121,7 +119,7 @@ public class Register {
     /**
      * Shut down the Register. This will close any open connections
      * and stop the regular re-registration.
-     **/
+     */
     public void shutdown() {
         updateTask.kill();
         orb.transport().perform(new Runnable() {
@@ -133,7 +131,7 @@ public class Register {
      * Register a service with the slobrok cluster.
      *
      * @param name service name
-     **/
+     */
     public synchronized void registerName(String name) {
         if (names.indexOf(name) >= 0) {
             return;
@@ -148,7 +146,7 @@ public class Register {
      * Unregister a service with the slobrok cluster
      *
      * @param name service name
-     **/
+     */
     public synchronized void unregisterName(String name) {
         discard(names, name);
         discard(pending, name);
@@ -164,15 +162,11 @@ public class Register {
             reqDone = false;
             if (req.isError()) {
                 if (req.errorCode() != ErrorCode.METHOD_FAILED) {
-                    log.log(Level.FINE, "register failed: "
-                            + req.errorMessage()
-                            + " (code " + req.errorCode() + ")");
+                    log.log(Level.FINE, "register failed: " + req.errorMessage() + " (code " + req.errorCode() + ")");
                     target.close();
                     target = null;
                 } else {
-                    log.log(Level.WARNING, "register failed: "
-                            + req.errorMessage()
-                            + " (code " + req.errorCode() + ")");
+                    log.log(Level.WARNING, "register failed: " + req.errorMessage() + " (code " + req.errorCode() + ")");
                 }
             } else {
                 backOff.reset();
@@ -192,13 +186,10 @@ public class Register {
             if (currSlobrok == null) {
                 double delay = backOff.get();
                 updateTask.schedule(delay);
-                if (backOff.shouldWarn(delay)) {
-                    log.log(Level.WARNING, "slobrok connection problems "
-                            + "(retry in " + delay + " seconds) to: " + slobroks);
-                } else {
-                    log.log(Level.FINE, "slobrok retry in " + delay
-                            + " seconds");
-                }
+                if (backOff.shouldWarn(delay))
+                    log.log(Level.WARNING, "slobrok connection problems (retry in " + delay + " seconds) to: " + slobroks);
+                else
+                    log.log(Level.FINE, "slobrok retry in " + delay + " seconds");
                 return;
             }
             target = orb.connect(new Spec(currSlobrok));
@@ -207,16 +198,14 @@ public class Register {
                 pending.addAll(names);
             }
         }
-        boolean rem  = false;
-        boolean reg  = false;
+        boolean unregister = false;
         String  name;
         synchronized (this) {
             if (unreg.size() > 0) {
                 name = unreg.remove(unreg.size() - 1);
-                rem = true;
+                unregister = true;
             } else if (pending.size() > 0) {
                 name = pending.remove(pending.size() - 1);
-                reg = true;
             } else {
                 pending.addAll(names);
                 log.log(Level.FINE, "done, reschedule in 30s");
@@ -225,13 +214,13 @@ public class Register {
             }
         }
 
-        if (rem) {
+        if (unregister) {
             req = new Request("slobrok.unregisterRpcServer");
             req.parameters().add(new StringValue(name));
             log.log(Level.FINE, "unregister [" + name + "]");
             req.parameters().add(new StringValue(mySpec));
             target.invokeAsync(req, 35.0, reqWait);
-        } else if (reg) {
+        } else { // register
             req = new Request("slobrok.registerRpcServer");
             req.parameters().add(new StringValue(name));
             log.log(Level.FINE, "register [" + name + "]");
@@ -246,8 +235,7 @@ public class Register {
     }
 
     private void handleRpcUnreg(Request req) {
-        log.log(Level.WARNING, "unregistered name "
-                + req.parameters().get(0).asString());
+        log.log(Level.WARNING, "unregistered name " + req.parameters().get(0).asString());
     }
 
     /**
@@ -266,4 +254,5 @@ public class Register {
             target = null;
         }
     }
+
 }
diff --git a/jrt/src/com/yahoo/jrt/slobrok/server/Slobrok.java b/jrt/src/com/yahoo/jrt/slobrok/server/Slobrok.java
index 085489897b5..3c81f9618f8 100644
--- a/jrt/src/com/yahoo/jrt/slobrok/server/Slobrok.java
+++ b/jrt/src/com/yahoo/jrt/slobrok/server/Slobrok.java
@@ -5,79 +5,16 @@ import com.yahoo.jrt.*;
 
 import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 public class Slobrok {
 
-    private class RegisterCallback implements RequestWaiter {
-
-        Request registerReq;
-        String  name;
-        String  spec;
-        Target  target;
-
-        public RegisterCallback(Request req, String name, String spec) {
-            req.detach();
-            registerReq = req;
-            this.name = name;
-            this.spec = spec;
-            target = orb.connect(new Spec(spec));
-            Request cbReq = new Request("slobrok.callback.listNamesServed");
-            target.invokeAsync(cbReq, 5.0, this);
-        }
-
-        public void handleRequestDone(Request req) {
-            if (!req.checkReturnTypes("S")) {
-                registerReq.setError(ErrorCode.METHOD_FAILED, "error during register callback: "
-                                     + req.errorMessage());
-                registerReq.returnRequest();
-                target.close();
-                return;
-            }
-            String[] names = req.returnValues().get(0).asStringArray();
-            boolean found = false;
-            for (String n : names) {
-                if (n.equals(name)) {
-                    found = true;
-                }
-            }
-            if (!found) {
-                registerReq.setError(ErrorCode.METHOD_FAILED, "register failed: "
-                                     + "served names does not contain name");
-                registerReq.returnRequest();
-                target.close();
-                return;
-            }
-            handleRegisterCallbackDone(registerReq, name, spec, target);
-        }
-    }
-
-    private class FetchMirror implements Runnable {
-        public final Request req;
-        public final Task    task;
-
-        public FetchMirror(Request req, int timeout) {
-            req.detach();
-            this.req = req;
-            task = orb.transport().createTask(this);
-            task.schedule(((double)timeout)/1000.0);
-        }
-        public void run() { // timeout
-            handleFetchMirrorTimeout(this);
-        }
-    }
-
-    private class TargetMonitor implements TargetWatcher {
-        public void notifyTargetInvalid(Target target) {
-            handleTargetDown(target);
-        }
-    }
-
     Supervisor             orb;
     Acceptor               listener;
-    HashMap<String,String> services     = new HashMap<String,String>();
-    ArrayList<FetchMirror> pendingFetch = new ArrayList<FetchMirror>();
-    HashMap<String,Target> targets      = new HashMap<String,Target>();
+    private Map<String,String> services = new HashMap<>();
+    List<FetchMirror> pendingFetch = new ArrayList<>();
+    Map<String,Target> targets = new HashMap<>();
     TargetMonitor          monitor      = new TargetMonitor();
     int                    gencnt       = 1;
 
@@ -123,15 +60,11 @@ public class Slobrok {
         handleFetchMirrorFlush();
     }
 
-    private void handleRegisterCallbackDone(Request req,
-                                            String name, String spec,
-                                            Target target)
-    {
+    private void handleRegisterCallbackDone(Request req, String name, String spec, Target target){
         String stored = services.get(name);
         if (stored != null) { // too late
-            if (!stored.equals(spec)) {
-                req.setError(ErrorCode.METHOD_FAILED,
-                             "service '" + name + "' registered with another spec");
+            if ( ! stored.equals(spec)) {
+                req.setError(ErrorCode.METHOD_FAILED, "service '" + name + "' registered with another spec");
             }
             req.returnRequest();
             target.close();
@@ -153,8 +86,8 @@ public class Slobrok {
     }
 
     private void dumpServices(Request req) {
-        ArrayList<String> names = new ArrayList<String>();
-        ArrayList<String> specs = new ArrayList<String>();
+        List<String> names = new ArrayList<>();
+        List<String> specs = new ArrayList<>();
         for (Map.Entry<String,String> entry : services.entrySet()) {
             names.add(entry.getKey());
             specs.add(entry.getValue());
@@ -225,12 +158,8 @@ public class Slobrok {
         if (stored == null) {
             new RegisterCallback(req, name, spec);
         } else {
-            if (stored.equals(spec)) {
-                // ok, already stored
-            } else {
-                req.setError(ErrorCode.METHOD_FAILED,
-                             "service '" + name + "' registered with another spec");
-            }
+            if ( ! stored.equals(spec))
+                req.setError(ErrorCode.METHOD_FAILED, "service '" + name + "' registered with another spec");
         }
     }
 
@@ -267,4 +196,67 @@ public class Slobrok {
         }
     }
 
+    private class RegisterCallback implements RequestWaiter {
+
+        Request registerReq;
+        String  name;
+        String  spec;
+        Target  target;
+
+        public RegisterCallback(Request req, String name, String spec) {
+            req.detach();
+            registerReq = req;
+            this.name = name;
+            this.spec = spec;
+            target = orb.connect(new Spec(spec));
+            Request cbReq = new Request("slobrok.callback.listNamesServed");
+            target.invokeAsync(cbReq, 5.0, this);
+        }
+
+        @Override
+        public void handleRequestDone(Request req) {
+            if ( ! req.checkReturnTypes("S")) {
+                registerReq.setError(ErrorCode.METHOD_FAILED, "error during register callback: " + req.errorMessage());
+                registerReq.returnRequest();
+                target.close();
+                return;
+            }
+            String[] names = req.returnValues().get(0).asStringArray();
+            boolean found = false;
+            for (String n : names) {
+                if (n.equals(name)) {
+                    found = true;
+                }
+            }
+            if (!found) {
+                registerReq.setError(ErrorCode.METHOD_FAILED, "register failed: served names does not contain name");
+                registerReq.returnRequest();
+                target.close();
+                return;
+            }
+            handleRegisterCallbackDone(registerReq, name, spec, target);
+        }
+    }
+
+    private class FetchMirror implements Runnable {
+        public final Request req;
+        public final Task    task;
+
+        public FetchMirror(Request req, int timeout) {
+            req.detach();
+            this.req = req;
+            task = orb.transport().createTask(this);
+            task.schedule(((double)timeout)/1000.0);
+        }
+        public void run() { // timeout
+            handleFetchMirrorTimeout(this);
+        }
+    }
+
+    private class TargetMonitor implements TargetWatcher {
+        public void notifyTargetInvalid(Target target) {
+            handleTargetDown(target);
+        }
+    }
+
 }