diff --git a/src/java.base/share/classes/java/text/DateFormatSymbols.java b/src/java.base/share/classes/java/text/DateFormatSymbols.java
index 9fff6a7c4d4..c8542ff17ee 100644
--- a/src/java.base/share/classes/java/text/DateFormatSymbols.java
+++ b/src/java.base/share/classes/java/text/DateFormatSymbols.java
@@ -145,10 +145,12 @@ public class DateFormatSymbols implements Serializable, Cloneable {
      * @throws     java.util.MissingResourceException
      *             if the resources for the specified locale cannot be
      *             found or cannot be loaded.
+     * @throws     NullPointerException if {@code locale} is null
      */
     public DateFormatSymbols(Locale locale)
     {
-        initializeData(locale);
+        initializeData(Objects.requireNonNull(locale,
+            "locale should not be null"));
     }
 
     /**
@@ -344,6 +346,7 @@ public class DateFormatSymbols implements Serializable, Cloneable {
      * @since 1.6
      */
     public static final DateFormatSymbols getInstance(Locale locale) {
+        Objects.requireNonNull(locale, "locale should not be null");
         DateFormatSymbols dfs = getProviderInstance(locale);
         if (dfs != null) {
             return dfs;
diff --git a/src/java.base/share/classes/java/text/DecimalFormatSymbols.java b/src/java.base/share/classes/java/text/DecimalFormatSymbols.java
index c255b93bd98..fe512e9cc26 100644
--- a/src/java.base/share/classes/java/text/DecimalFormatSymbols.java
+++ b/src/java.base/share/classes/java/text/DecimalFormatSymbols.java
@@ -115,7 +115,8 @@ public class DecimalFormatSymbols implements Cloneable, Serializable {
      * @throws    NullPointerException if {@code locale} is null
      */
     public DecimalFormatSymbols(Locale locale) {
-        initialize(locale);
+        initialize(Objects.requireNonNull(locale,
+            "locale should not be null"));
     }
 
     /**
@@ -180,6 +181,7 @@ public class DecimalFormatSymbols implements Cloneable, Serializable {
      * @since 1.6
      */
     public static final DecimalFormatSymbols getInstance(Locale locale) {
+        Objects.requireNonNull(locale, "locale should not be null");
         LocaleProviderAdapter adapter;
         adapter = LocaleProviderAdapter.getAdapter(DecimalFormatSymbolsProvider.class, locale);
         DecimalFormatSymbolsProvider provider = adapter.getDecimalFormatSymbolsProvider();
diff --git a/test/jdk/java/text/Format/DateFormat/IntlTestDateFormatSymbols.java b/test/jdk/java/text/Format/DateFormat/IntlTestDateFormatSymbols.java
index e3cb841b5c6..84b828f36c5 100644
--- a/test/jdk/java/text/Format/DateFormat/IntlTestDateFormatSymbols.java
+++ b/test/jdk/java/text/Format/DateFormat/IntlTestDateFormatSymbols.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -24,6 +24,7 @@
 /*
  * @test
  * @summary test International Date Format Symbols
+ * @bug 8366517
  * @run junit IntlTestDateFormatSymbols
  */
 /*
@@ -43,6 +44,7 @@ import java.util.*;
 
 import org.junit.jupiter.api.Test;
 
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.fail;
 
 public class IntlTestDateFormatSymbols
@@ -205,4 +207,10 @@ public class IntlTestDateFormatSymbols
             fail("ERROR: Clone failed");
         }
     }
+
+    @Test
+    void nullLocaleTest() {
+        assertThrows(NullPointerException.class, () -> new DateFormatSymbols(null));
+        assertThrows(NullPointerException.class, () -> DateFormatSymbols.getInstance(null));
+    }
 }
diff --git a/test/jdk/java/text/Format/NumberFormat/IntlTestDecimalFormatSymbols.java b/test/jdk/java/text/Format/NumberFormat/IntlTestDecimalFormatSymbols.java
index 75c9199c95b..c370440c932 100644
--- a/test/jdk/java/text/Format/NumberFormat/IntlTestDecimalFormatSymbols.java
+++ b/test/jdk/java/text/Format/NumberFormat/IntlTestDecimalFormatSymbols.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -23,7 +23,7 @@
 
 /*
  * @test
- * @bug 8282625
+ * @bug 8282625 8366517
  * @summary test International Decimal Format Symbols
  * @run junit IntlTestDecimalFormatSymbols
  */
@@ -44,6 +44,7 @@ import java.util.*;
 
 import org.junit.jupiter.api.Test;
 
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.fail;
 
 public class IntlTestDecimalFormatSymbols
@@ -146,4 +147,10 @@ public class IntlTestDecimalFormatSymbols
             fail("ERROR: Clone failed");
         }
     }
+
+    @Test
+    void nullLocaleTest() {
+        assertThrows(NullPointerException.class, () -> new DecimalFormatSymbols(null));
+        assertThrows(NullPointerException.class, () -> DecimalFormatSymbols.getInstance(null));
+    }
 }