--- jsr166/src/test/tck/JSR166TestCase.java	2018/12/12 16:59:55	1.251
+++ jsr166/src/test/tck/JSR166TestCase.java	2019/04/24 17:36:09	1.254
@@ -460,6 +460,12 @@ public class JSR166TestCase extends Test
     public static boolean atLeastJava9()  { return JAVA_CLASS_VERSION >= 53.0; }
     public static boolean atLeastJava10() { return JAVA_CLASS_VERSION >= 54.0; }
     public static boolean atLeastJava11() { return JAVA_CLASS_VERSION >= 55.0; }
+    public static boolean atLeastJava12() { return JAVA_CLASS_VERSION >= 56.0; }
+    public static boolean atLeastJava13() { return JAVA_CLASS_VERSION >= 57.0; }
+    public static boolean atLeastJava14() { return JAVA_CLASS_VERSION >= 58.0; }
+    public static boolean atLeastJava15() { return JAVA_CLASS_VERSION >= 59.0; }
+    public static boolean atLeastJava16() { return JAVA_CLASS_VERSION >= 60.0; }
+    public static boolean atLeastJava17() { return JAVA_CLASS_VERSION >= 61.0; }
 
     /**
      * Collects all JSR166 unit tests as one suite.
@@ -511,6 +517,7 @@ public class JSR166TestCase extends Test
             ExecutorsTest.suite(),
             ExecutorCompletionServiceTest.suite(),
             FutureTaskTest.suite(),
+            HashtableTest.suite(),
             LinkedBlockingDequeTest.suite(),
             LinkedBlockingQueueTest.suite(),
             LinkedListTest.suite(),
@@ -1744,12 +1751,11 @@ public class JSR166TestCase extends Test
         }
     }
 
-    void assertImmutable(final Object o) {
+    void assertImmutable(Object o) {
         if (o instanceof Collection) {
             assertThrows(
                 UnsupportedOperationException.class,
-                new Runnable() { public void run() {
-                        ((Collection) o).add(null);}});
+                () -> ((Collection) o).add(null));
         }
     }
 
@@ -1809,8 +1815,8 @@ public class JSR166TestCase extends Test
     }
 
     public void assertThrows(Class<? extends Throwable> expectedExceptionClass,
-                             Runnable... throwingActions) {
-        for (Runnable throwingAction : throwingActions) {
+                             Action... throwingActions) {
+        for (Action throwingAction : throwingActions) {
             boolean threw = false;
             try { throwingAction.run(); }
             catch (Throwable t) {