diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/StarredChangesUtil.java b/gerrit-server/src/main/java/com/google/gerrit/server/StarredChangesUtil.java
index 23ca117..61ab3a1 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/StarredChangesUtil.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/StarredChangesUtil.java
@@ -123,7 +123,7 @@
     }
   }
 
-  public static class IllegalLabelException extends IllegalArgumentException {
+  public static class IllegalLabelException extends Exception {
     private static final long serialVersionUID = 1L;
 
     IllegalLabelException(String message) {
@@ -200,7 +200,7 @@
       Change.Id changeId,
       Set<String> labelsToAdd,
       Set<String> labelsToRemove)
-      throws OrmException {
+      throws OrmException, IllegalLabelException {
     try (Repository repo = repoManager.openRepository(allUsers)) {
       String refName = RefNames.refsStarredChanges(changeId, accountId);
       StarRef old = readLabels(repo, refName);
@@ -304,7 +304,7 @@
     }
   }
 
-  public void ignore(ChangeResource rsrc) throws OrmException {
+  public void ignore(ChangeResource rsrc) throws OrmException, IllegalLabelException {
     star(
         rsrc.getUser().asIdentifiedUser().getAccountId(),
         rsrc.getProject(),
@@ -313,7 +313,7 @@
         ImmutableSet.of());
   }
 
-  public void unignore(ChangeResource rsrc) throws OrmException {
+  public void unignore(ChangeResource rsrc) throws OrmException, IllegalLabelException {
     star(
         rsrc.getUser().asIdentifiedUser().getAccountId(),
         rsrc.getProject(),
@@ -335,7 +335,7 @@
   }
 
   public void mute(Account.Id accountId, Project.NameKey project, Change change)
-      throws OrmException {
+      throws OrmException, IllegalLabelException {
     star(
         accountId,
         project,
@@ -345,7 +345,7 @@
   }
 
   public void unmute(Account.Id accountId, Project.NameKey project, Change change)
-      throws OrmException {
+      throws OrmException, IllegalLabelException {
     star(
         accountId,
         project,
@@ -375,7 +375,7 @@
   }
 
   public static ObjectId writeLabels(Repository repo, Collection<String> labels)
-      throws IOException {
+      throws IOException, InvalidLabelsException {
     validateLabels(labels);
     try (ObjectInserter oi = repo.newObjectInserter()) {
       ObjectId id =
@@ -387,13 +387,14 @@
     }
   }
 
-  private static void checkMutuallyExclusiveLabels(Set<String> labels) {
+  private static void checkMutuallyExclusiveLabels(Set<String> labels)
+      throws MutuallyExclusiveLabelsException {
     if (labels.containsAll(ImmutableSet.of(DEFAULT_LABEL, IGNORE_LABEL))) {
       throw new MutuallyExclusiveLabelsException(DEFAULT_LABEL, IGNORE_LABEL);
     }
   }
 
-  private static void validateLabels(Collection<String> labels) {
+  private static void validateLabels(Collection<String> labels) throws InvalidLabelsException {
     if (labels == null) {
       return;
     }
@@ -411,7 +412,7 @@
 
   private void updateLabels(
       Repository repo, String refName, ObjectId oldObjectId, Collection<String> labels)
-      throws IOException, OrmException {
+      throws IOException, OrmException, InvalidLabelsException {
     try (RevWalk rw = new RevWalk(repo)) {
       RefUpdate u = repo.updateRef(refName);
       u.setExpectedOldObjectId(oldObjectId);
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/account/StarredChanges.java b/gerrit-server/src/main/java/com/google/gerrit/server/account/StarredChanges.java
index 0e84c03..ad73a69 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/account/StarredChanges.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/account/StarredChanges.java
@@ -187,7 +187,7 @@
 
     @Override
     public Response<?> apply(AccountResource.StarredChange rsrc, EmptyInput in)
-        throws AuthException, OrmException, IOException {
+        throws AuthException, OrmException, IOException, IllegalLabelException {
       if (self.get() != rsrc.getUser()) {
         throw new AuthException("not allowed remove starred change");
       }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java b/gerrit-server/src/main/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java
index fe665a4..d006c7e 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java
@@ -49,6 +49,7 @@
 import com.google.gerrit.extensions.restapi.Response;
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.server.StarredChangesUtil;
+import com.google.gerrit.server.StarredChangesUtil.IllegalLabelException;
 import com.google.gerrit.server.change.Abandon;
 import com.google.gerrit.server.change.ChangeIncludedIn;
 import com.google.gerrit.server.change.ChangeJson;
@@ -668,7 +669,7 @@
       } else {
         unignore.apply(change, new Unignore.Input());
       }
-    } catch (OrmException e) {
+    } catch (OrmException | IllegalLabelException e) {
       throw asRestApiException("Cannot ignore change", e);
     }
   }
@@ -692,7 +693,7 @@
       } else {
         unmute.apply(change, new Unmute.Input());
       }
-    } catch (OrmException e) {
+    } catch (OrmException | IllegalLabelException e) {
       throw asRestApiException("Cannot mute change", e);
     }
   }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/Ignore.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/Ignore.java
index 11e31df..46dabdf 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/Ignore.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/Ignore.java
@@ -21,6 +21,7 @@
 import com.google.gerrit.extensions.restapi.RestModifyView;
 import com.google.gerrit.extensions.webui.UiAction;
 import com.google.gerrit.server.StarredChangesUtil;
+import com.google.gerrit.server.StarredChangesUtil.IllegalLabelException;
 import com.google.gerrit.server.StarredChangesUtil.MutuallyExclusiveLabelsException;
 import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
@@ -52,7 +53,7 @@
 
   @Override
   public Response<String> apply(ChangeResource rsrc, Input input)
-      throws RestApiException, OrmException {
+      throws RestApiException, OrmException, IllegalLabelException {
     try {
       if (rsrc.isUserOwner()) {
         throw new BadRequestException("cannot ignore own change");
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/Mute.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/Mute.java
index c7e0603..5fb3ef6 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/Mute.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/Mute.java
@@ -21,6 +21,7 @@
 import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.StarredChangesUtil;
+import com.google.gerrit.server.StarredChangesUtil.IllegalLabelException;
 import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
@@ -53,7 +54,7 @@
 
   @Override
   public Response<String> apply(ChangeResource rsrc, Input input)
-      throws RestApiException, OrmException {
+      throws RestApiException, OrmException, IllegalLabelException {
     if (rsrc.isUserOwner() || isMuted(rsrc.getChange())) {
       // early exit for own changes and already muted changes
       return Response.ok("");
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/Unignore.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/Unignore.java
index 2179ec5f..a10e754 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/Unignore.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/Unignore.java
@@ -19,6 +19,7 @@
 import com.google.gerrit.extensions.restapi.RestModifyView;
 import com.google.gerrit.extensions.webui.UiAction;
 import com.google.gerrit.server.StarredChangesUtil;
+import com.google.gerrit.server.StarredChangesUtil.IllegalLabelException;
 import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
@@ -49,7 +50,7 @@
 
   @Override
   public Response<String> apply(ChangeResource rsrc, Input input)
-      throws RestApiException, OrmException {
+      throws RestApiException, OrmException, IllegalLabelException {
     if (isIgnored(rsrc)) {
       stars.unignore(rsrc);
     }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/Unmute.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/Unmute.java
index d50bd20..586f3e6 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/Unmute.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/Unmute.java
@@ -21,6 +21,7 @@
 import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.StarredChangesUtil;
+import com.google.gerrit.server.StarredChangesUtil.IllegalLabelException;
 import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
@@ -54,7 +55,7 @@
 
   @Override
   public Response<String> apply(ChangeResource rsrc, Input input)
-      throws RestApiException, OrmException {
+      throws RestApiException, OrmException, IllegalLabelException {
     if (rsrc.isUserOwner() || !isMuted(rsrc.getChange())) {
       // early exit for own changes and not muted changes
       return Response.ok("");
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/schema/Schema_123.java b/gerrit-server/src/main/java/com/google/gerrit/server/schema/Schema_123.java
index ec63141..31cfd5d 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/schema/Schema_123.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/schema/Schema_123.java
@@ -21,6 +21,7 @@
 import com.google.gerrit.reviewdb.client.RefNames;
 import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.StarredChangesUtil;
+import com.google.gerrit.server.StarredChangesUtil.IllegalLabelException;
 import com.google.gerrit.server.config.AllUsersName;
 import com.google.gerrit.server.git.GitRepositoryManager;
 import com.google.gwtorm.jdbc.JdbcSchema;
@@ -78,7 +79,7 @@
                 ObjectId.zeroId(), id, RefNames.refsStarredChanges(e.getValue(), e.getKey())));
       }
       bru.execute(rw, new TextProgressMonitor());
-    } catch (IOException ex) {
+    } catch (IOException | IllegalLabelException ex) {
       throw new OrmException(ex);
     }
   }