diff --git a/test/129-ThreadGetId/src/Main.java b/test/129-ThreadGetId/src/Main.java
index 9934bba..5aefd17 100644
--- a/test/129-ThreadGetId/src/Main.java
+++ b/test/129-ThreadGetId/src/Main.java
@@ -22,6 +22,7 @@
 
     public static void main(String[] args) throws Exception {
         final Thread[] threads = new Thread[numberOfThreads];
+        test_getStackTraces();
         for (int t = 0; t < threads.length; t++) {
             threads[t] = new Thread(new Main());
             threads[t].start();
@@ -32,6 +33,19 @@
         System.out.println("Finishing");
     }
 
+    static void test_getStackTraces() {
+        // Check all the current threads for positive IDs.
+        Map<Thread, StackTraceElement[]> map = Thread.getAllStackTraces();
+        for (Map.Entry<Thread, StackTraceElement[]> pair : map.entrySet()) {
+            Thread thread = pair.getKey();
+            // Expect empty stack trace since we do not support suspending the GC thread for
+            // obtaining stack traces. See b/28261069.
+            if (thread.getName().equals("HeapTaskDaemon")) {
+                System.out.println(thread.getName() + " depth " + pair.getValue().length); 
+            }
+        }
+    }
+
     public void test_getId() {
         if (Thread.currentThread().getId() <= 0) {
             System.out.println("current thread's ID is not positive");