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

@@ -531,12 +531,12 @@
     @Deprecated(since="9")
     public T newInstance()
         throws InstantiationException, IllegalAccessException
     {
         if (this.isValue()) {
-            throw new UnsupportedOperationException("newInstance on a value class "
-                + this.getName());
+            throw new IllegalAccessException(
+                "cannot create new instance of value class " + this.getName());
         }
 
         SecurityManager sm = System.getSecurityManager();
         if (sm != null) {
             checkMemberAccess(sm, Member.PUBLIC, Reflection.getCallerClass(), false);