diff --git a/src/java.base/share/classes/java/util/concurrent/ConcurrentHashMap.java b/src/java.base/share/classes/java/util/concurrent/ConcurrentHashMap.java
index 117bb72a1a6..884a4b3865f 100644
--- a/src/java.base/share/classes/java/util/concurrent/ConcurrentHashMap.java
+++ b/src/java.base/share/classes/java/util/concurrent/ConcurrentHashMap.java
@@ -4416,8 +4416,8 @@ public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
     /**
      * Base class for views.
      */
-    abstract static class CollectionView<K,V,E>
-        implements Collection<E>, java.io.Serializable {
+    abstract static sealed class CollectionView<K,V,E>
+        implements Collection<E>, java.io.Serializable permits EntrySetView, KeySetView, ValuesView {
         private static final long serialVersionUID = 7249069246763182397L;
         final ConcurrentHashMap<K,V> map;
         CollectionView(ConcurrentHashMap<K,V> map)  { this.map = map; }
@@ -4589,7 +4589,7 @@ public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
      *
      * @since 1.8
      */
-    public static class KeySetView<K,V> extends CollectionView<K,V,K>
+    public static final class KeySetView<K,V> extends CollectionView<K,V,K>
         implements Set<K>, java.io.Serializable {
         private static final long serialVersionUID = 7249069246763182397L;
         @SuppressWarnings("serial") // Conditionally serializable