diff --git a/src/main/java/com/googlesource/gerrit/plugins/automerger/FailedMergeException.java b/src/main/java/com/googlesource/gerrit/plugins/automerger/FailedMergeException.java
index 96c567c..aa0850c 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/automerger/FailedMergeException.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/automerger/FailedMergeException.java
@@ -22,6 +22,7 @@
 
 /** Exception class for merge conflicts. */
 class FailedMergeException extends Exception {
+  private static final long serialVersionUID = 1L;
   private static final int MAX_CONFLICT_MESSAGE_LENGTH = 10000;
   public final String currentRevision;
   public final String conflictMessage;
diff --git a/src/main/java/com/googlesource/gerrit/plugins/automerger/InvalidQueryParameterException.java b/src/main/java/com/googlesource/gerrit/plugins/automerger/InvalidQueryParameterException.java
index 8915f96..7cc3780 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/automerger/InvalidQueryParameterException.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/automerger/InvalidQueryParameterException.java
@@ -15,6 +15,7 @@
 
 /** Exception class for invalid query parameters. */
 class InvalidQueryParameterException extends Exception {
+  private static final long serialVersionUID = 1L;
 
   InvalidQueryParameterException(String message) {
     super(message);