Address review feedback

core/src/main/java/hudson/Functions.java

@@ -179,6 +179,7 @@ import org.kohsuke.accmod.restrictions.DoNotUse;
 @SuppressWarnings("rawtypes")
 public class Functions {
     private static final AtomicLong iota = new AtomicLong();
+    private static Logger LOGGER = Logger.getLogger(Functions.class.getName());
 
     public Functions() {
     }
@@ -651,7 +652,7 @@ public class Functions {
         try {
             ExtensionList.lookupSingleton(AutoRefresh.class).recordRequest(request, refresh);
         } catch (Exception e) {
-            // ignore telemetry problems
+            LOGGER.log(Level.FINE, "Failed to record auto refresh status in telemetry", e);
         }
     }
 

core/src/main/java/jenkins/telemetry/impl/AutoRefresh.java

@@ -54,7 +54,7 @@ public class AutoRefresh extends Telemetry {
     @Nonnull
     @Override
     public String getDisplayName() {
-        return "Use of auto refresh feature";
+        return Messages.AutoRefresh_DisplayName();
     }
 
     @Nonnull
@@ -66,7 +66,7 @@ public class AutoRefresh extends Telemetry {
     @Nonnull
     @Override
     public LocalDate getEnd() {
-        return LocalDate.of(2019, 4, 10);
+        return LocalDate.of(2019, 5, 31);
     }
 
     @Override
@@ -74,8 +74,11 @@ public class AutoRefresh extends Telemetry {
         if (sessionsBySetting.size() == 0) {
             return null;
         }
-        Map<Boolean, Set<String>> currentSessions = new TreeMap<>(sessionsBySetting);
-        sessionsBySetting.clear();
+        Map<Boolean, Set<String>> currentSessions;
+        synchronized (sessionsBySetting) {
+            currentSessions = new TreeMap<>(sessionsBySetting);
+            sessionsBySetting.clear();
+        }
 
         JSONObject payload = new JSONObject();
         for (Map.Entry<Boolean, Set<String>> entry : currentSessions.entrySet()) {
@@ -94,8 +97,10 @@ public class AutoRefresh extends Telemetry {
         HttpSession session = request.getSession(false);
         if (session != null) {
             String sessionId = session.getId();
-            sessionsBySetting.putIfAbsent(enabled, new HashSet<>());
-            sessionsBySetting.get(enabled).add(sessionId);
+            synchronized (sessionsBySetting) {
+                sessionsBySetting.putIfAbsent(enabled, new HashSet<>());
+                sessionsBySetting.get(enabled).add(sessionId);
+            }
         }
     }
 }

core/src/main/resources/jenkins/telemetry/impl/AutoRefresh/description.jelly

 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core">
-    This trial collects information about the "Auto Refresh" feature to determine whether use of the feature is used enough to not remove it in a future release of Jenkins.
+    This trial collects information about the "Auto Refresh" feature to determine whether the feature is used enough to not remove it in a future release of Jenkins.
     We collect the number of HTTP sessions that have the feature (typically controlled via a cookie) enabled or disabled.
 </j:jelly>

core/src/main/resources/jenkins/telemetry/impl/Messages.properties

+AutoRefresh.DisplayName = Use of auto refresh feature
\ No newline at end of file