diff a/test/langtools/tools/javac/valhalla/value-objects/DuplicateValueClassWarnings.java b/test/langtools/tools/javac/valhalla/value-objects/DuplicateValueClassWarnings.java
--- /dev/null
+++ b/test/langtools/tools/javac/valhalla/value-objects/DuplicateValueClassWarnings.java
@@ -0,0 +1,10 @@
+/*
+ * @test /nodynamiccopyright/
+ * @bug 8386995
+ * @summary Value class preview feature warning should be emitted only once
+ * @enablePreview
+ * @compile/ref=DuplicateValueClassWarnings.out -Xlint:preview -XDrawDiagnostics ${test.file}
+ */
+
+public value class DuplicateValueClassWarnings {
+}