Add a test for virtual cleaner threads

Author: pron

test/jdk/java/lang/ref/CleanerTest.java

@@ -58,8 +58,12 @@
  * @modules java.base/jdk.internal.misc
  *          java.base/jdk.internal.ref
  *          java.management
+ * @compile --enable-preview -source ${jdk.version} CleanerTest.java
  * @run driver jdk.test.lib.helpers.ClassFileInstaller sun.hotspot.WhiteBox
- * @run testng/othervm
+ * @run testng/othervm --enable-preview
+ *      -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
+ *      -verbose:gc CleanerTest
+ * @run testng/othervm --enable-preview -Dtest.virtualThread=true
  *      -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
  *      -verbose:gc CleanerTest
  */
@@ -72,6 +76,14 @@ public class CleanerTest {
     // Access to WhiteBox utilities
     static final WhiteBox whitebox = WhiteBox.getWhiteBox();
 
+    static final boolean VIRTUAL = Boolean.getBoolean("test.virtualThread");
+
+    Cleaner create() {
+        return VIRTUAL
+            ? Cleaner.create(Thread.ofVirtual().factory())
+            : Cleaner.create();
+    }
+
     /**
      * Test that sequences of the various actions on a Reference
      * and on the Cleanable instance have the desired result.
@@ -85,7 +97,7 @@ public class CleanerTest {
     @Test
     @SuppressWarnings("unchecked")
     void testCleanableActions() {
-        Cleaner cleaner = Cleaner.create();
+        Cleaner cleaner = create();
 
         // Individually
         generateCases(cleaner, c -> c.clearRef());
@@ -112,7 +124,7 @@ void testCleanableActions() {
     @Test
     @SuppressWarnings("unchecked")
     void testRefSubtypes() {
-        Cleaner cleaner = Cleaner.create();
+        Cleaner cleaner = create();
 
         // Individually
         generateCasesInternal(cleaner, c -> c.clearRef());
@@ -251,7 +263,7 @@ void verifyGetRef(CleanableCase test) {
     @Test
     void testCleanerTermination() {
         ReferenceQueue<Object> queue = new ReferenceQueue<>();
-        Cleaner service = Cleaner.create();
+        Cleaner service = create();
 
         PhantomReference<Object> ref = new PhantomReference<>(service, queue);
         System.gc();
@@ -522,7 +534,7 @@ public String toString() {
     @Test
     @SuppressWarnings("rawtypes")
     void testReferentNotAvailable() {
-        Cleaner cleaner = Cleaner.create();
+        Cleaner cleaner = create();
         Semaphore s1 = new Semaphore(0);
 
         Object obj = new String("a new string");