diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/GerritSshApi.java b/src/main/java/com/googlesource/gerrit/plugins/replication/GerritSshApi.java
index 46c8892..ccd8bf4 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/GerritSshApi.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/GerritSshApi.java
@@ -27,8 +27,8 @@
 public class GerritSshApi implements AdminApi {
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
-  static int SSH_COMMAND_FAILED = -1;
-  private static String GERRIT_ADMIN_PROTOCOL_PREFIX = "gerrit+";
+  static final int SSH_COMMAND_FAILED = -1;
+  private static final String GERRIT_ADMIN_PROTOCOL_PREFIX = "gerrit+";
 
   protected final SshHelper sshHelper;
   protected final URIish uri;
diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/ReplicationTasksStorage.java b/src/main/java/com/googlesource/gerrit/plugins/replication/ReplicationTasksStorage.java
index 64397f9..39158f3 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/ReplicationTasksStorage.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/ReplicationTasksStorage.java
@@ -57,7 +57,7 @@
     }
   }
 
-  private static Gson GSON = new Gson();
+  private static final Gson GSON = new Gson();
 
   private final Path refUpdates;