src/java.base/share/classes/java/lang/ClassValue.java

@  rev 60626 : 8251397: NPE on ClassValue.ClassValueMap.cacheArray
|  Reviewed-by: aph
~

@@ -27,10 +27,12 @@
 
 import java.util.WeakHashMap;
 import java.lang.ref.WeakReference;
 import java.util.concurrent.atomic.AtomicInteger;
 
+import jdk.internal.misc.Unsafe;
+
 import static java.lang.ClassValue.ClassValueMap.probeHomeLocation;
 import static java.lang.ClassValue.ClassValueMap.probeBackupLocations;
 
 /**
  * Lazily associate a computed value with (potentially) every type.

@@ -409,15 +411,19 @@
          *  It would be pointless to make this much smaller than the Class and ClassValueMap objects themselves.
          *  Must be a power of 2.
          */
         private static final int INITIAL_ENTRIES = 32;
 
+        private static final Unsafe UNSAFE = Unsafe.getUnsafe();
+
         /** Build a backing map for ClassValues.
          *  Also, create an empty cache array and install it on the class.
          */
         ClassValueMap() {
             sizeCache(INITIAL_ENTRIES);
+            // Trailing release fence to get safe publication
+            UNSAFE.storeFence();
         }
 
         Entry<?>[] getCache() { return cacheArray; }
 
         /** Initiate a query.  Store a promise (placeholder) if there is no value yet. */