diff --git a/java/com/google/gerrit/server/notedb/ChangeNoteUtil.java b/java/com/google/gerrit/server/notedb/ChangeNoteUtil.java
index b23c1defb5..89326c89ff 100644
--- a/java/com/google/gerrit/server/notedb/ChangeNoteUtil.java
+++ b/java/com/google/gerrit/server/notedb/ChangeNoteUtil.java
@@ -23,7 +23,6 @@ import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.CharMatcher;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ListMultimap;
-import com.google.common.primitives.Ints;
 import com.google.gerrit.reviewdb.client.Account;
 import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.reviewdb.client.Comment;
@@ -158,18 +157,14 @@ public class ChangeNoteUtil {
 
   public Account.Id parseIdent(PersonIdent ident, Change.Id changeId)
       throws ConfigInvalidException {
-    String email = ident.getEmailAddress();
-    int at = email.indexOf('@');
-    if (at >= 0) {
-      String host = email.substring(at + 1, email.length());
-      if (host.equals(serverId)) {
-        Integer id = Ints.tryParse(email.substring(0, at));
-        if (id != null) {
-          return new Account.Id(id);
-        }
-      }
-    }
-    throw parseException(changeId, "invalid identity, expected <id>@%s: %s", serverId, email);
+    return NoteDbUtil.parseIdent(ident, serverId)
+        .orElseThrow(
+            () ->
+                parseException(
+                    changeId,
+                    "invalid identity, expected <id>@%s: %s",
+                    serverId,
+                    ident.getEmailAddress()));
   }
 
   private static boolean match(byte[] note, MutableInteger p, byte[] expected) {
diff --git a/java/com/google/gerrit/server/notedb/NoteDbUtil.java b/java/com/google/gerrit/server/notedb/NoteDbUtil.java
new file mode 100644
index 0000000000..59c4c62dd3
--- /dev/null
+++ b/java/com/google/gerrit/server/notedb/NoteDbUtil.java
@@ -0,0 +1,39 @@
+// Copyright (C) 2017 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.notedb;
+
+import com.google.common.primitives.Ints;
+import com.google.gerrit.reviewdb.client.Account;
+import java.util.Optional;
+import org.eclipse.jgit.lib.PersonIdent;
+
+public class NoteDbUtil {
+  public static Optional<Account.Id> parseIdent(PersonIdent ident, String serverId) {
+    String email = ident.getEmailAddress();
+    int at = email.indexOf('@');
+    if (at >= 0) {
+      String host = email.substring(at + 1, email.length());
+      if (host.equals(serverId)) {
+        Integer id = Ints.tryParse(email.substring(0, at));
+        if (id != null) {
+          return Optional.of(new Account.Id(id));
+        }
+      }
+    }
+    return Optional.empty();
+  }
+
+  private NoteDbUtil() {}
+}