diff --git a/src/main/org/firebirdsql/jdbc/FBObjectListener.java b/src/main/org/firebirdsql/jdbc/FBObjectListener.java
index ba7e08157..3f6f25b7c 100644
--- a/src/main/org/firebirdsql/jdbc/FBObjectListener.java
+++ b/src/main/org/firebirdsql/jdbc/FBObjectListener.java
@@ -20,6 +20,8 @@
 
 import org.firebirdsql.gds.ng.fields.RowValue;
 import org.firebirdsql.util.InternalApi;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import java.sql.ResultSet;
 import java.sql.SQLException;
@@ -37,6 +39,7 @@ private FBObjectListener() {
         // no instances
     }
 
+    @NullMarked
     public interface FetcherListener {
 
         /**
@@ -50,7 +53,7 @@ public interface FetcherListener {
          * @param newRow
          *         new row
          */
-        default void rowChanged(FBFetcher fetcher, RowValue newRow) throws SQLException {
+        default void rowChanged(FBFetcher fetcher, @Nullable RowValue newRow) throws SQLException {
             // do nothing
         }
 
@@ -59,6 +62,7 @@ default void rowChanged(FBFetcher fetcher, RowValue newRow) throws SQLException
     /**
      * Listener for the events generated by the result set.
      */
+    @NullMarked
     public interface ResultSetListener {
 
         /**
diff --git a/src/main/org/firebirdsql/jdbc/FBUpdatableFetcher.java b/src/main/org/firebirdsql/jdbc/FBUpdatableFetcher.java
index a1b137503..32952a47e 100644
--- a/src/main/org/firebirdsql/jdbc/FBUpdatableFetcher.java
+++ b/src/main/org/firebirdsql/jdbc/FBUpdatableFetcher.java
@@ -19,6 +19,8 @@
 package org.firebirdsql.jdbc;
 
 import org.firebirdsql.gds.ng.fields.RowValue;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import java.sql.SQLException;
 import java.sql.SQLNonTransientException;
@@ -44,13 +46,14 @@
  *
  * @since 5
  */
+@NullMarked
 final class FBUpdatableFetcher implements FBFetcher {
 
     private final FBFetcher fetcher;
     private final RowValue deletedRowMarker;
 
     private FBObjectListener.FetcherListener fetcherListener;
-    private Map<Integer, RowValue> modifiedRows = new HashMap<>();
+    private Map<Integer, @Nullable RowValue> modifiedRows = new HashMap<>();
 
     private int position;
     private List<RowValue> insertedRows = new ArrayList<>();
@@ -100,7 +103,7 @@ private boolean notifyInsertedRow(int position) throws SQLException {
         return notifyRow(position, rowValue);
     }
 
-    private boolean notifyRow(int position, RowValue originalRowValue) throws SQLException {
+    private boolean notifyRow(int position, @Nullable RowValue originalRowValue) throws SQLException {
         RowValue rowValue = modifiedRows.getOrDefault(position, originalRowValue);
         fetcherListener.rowChanged(fetcher, rowValue);
         return rowValue != null;
@@ -356,10 +359,10 @@ public boolean rowDeleted() throws SQLException {
 
     private static final class InternalFetcherListener implements FBObjectListener.FetcherListener {
 
-        RowValue lastReceivedRow;
+        @Nullable RowValue lastReceivedRow;
 
         @Override
-        public void rowChanged(FBFetcher fetcher, RowValue newRow) {
+        public void rowChanged(FBFetcher fetcher, @Nullable RowValue newRow) {
             lastReceivedRow = newRow;
         }
 
diff --git a/src/test/org/firebirdsql/jdbc/FBServerScrollFetcherTest.java b/src/test/org/firebirdsql/jdbc/FBServerScrollFetcherTest.java
index 5fefca159..2885333c5 100644
--- a/src/test/org/firebirdsql/jdbc/FBServerScrollFetcherTest.java
+++ b/src/test/org/firebirdsql/jdbc/FBServerScrollFetcherTest.java
@@ -544,7 +544,7 @@ execute block (records INTEGER = ?)
     }
 
     private int extractId(RowValue rowValue) {
-        return db.getDatatypeCoder().decodeInt(rowValue.getFieldData(0));
+        return rowValue != null ? db.getDatatypeCoder().decodeInt(rowValue.getFieldData(0)) : Integer.MIN_VALUE;
     }
 
 }
\ No newline at end of file
diff --git a/src/test/org/firebirdsql/jdbc/SimpleFetcherListener.java b/src/test/org/firebirdsql/jdbc/SimpleFetcherListener.java
index 875e1b3a5..bc2c3e234 100644
--- a/src/test/org/firebirdsql/jdbc/SimpleFetcherListener.java
+++ b/src/test/org/firebirdsql/jdbc/SimpleFetcherListener.java
@@ -19,6 +19,8 @@
 package org.firebirdsql.jdbc;
 
 import org.firebirdsql.gds.ng.fields.RowValue;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -26,16 +28,17 @@
 
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+@NullMarked
 final class SimpleFetcherListener implements FBObjectListener.FetcherListener {
 
-    final List<RowValue> receivedRows = new ArrayList<>();
+    final List<@Nullable RowValue> receivedRows = new ArrayList<>();
 
     @Override
-    public void rowChanged(FBFetcher fetcher, RowValue newRow) {
+    public void rowChanged(FBFetcher fetcher, @Nullable RowValue newRow) {
         receivedRows.add(newRow);
     }
 
-    void assertRow(int rowIndex, Consumer<RowValue> assertion) {
+    void assertRow(int rowIndex, Consumer<@Nullable RowValue> assertion) {
         assertTrue(0 <= rowIndex && rowIndex < receivedRows.size(), () -> "row index out of range: " + rowIndex);
         assertion.accept(receivedRows.get(rowIndex));
     }