--- a/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/oops/ObjectHeap.java	Tue May 21 00:52:04 2019 -0700
+++ b/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/oops/ObjectHeap.java	Tue May 21 10:34:57 2019 +0200
@@ -357,7 +357,9 @@
     // end.
 
     if (VM.getVM().getUseTLAB()) {
-      for (JavaThread thread = VM.getVM().getThreads().first(); thread != null; thread = thread.next()) {
+      Threads threads = VM.getVM().getThreads();
+      for (int i = 0; i < threads.getNumberOfThreads(); i++) {
+        JavaThread thread = threads.getJavaThreadAt(i);
         ThreadLocalAllocBuffer tlab = thread.tlab();
         if (tlab.start() != null) {
           if ((tlab.top() == null) || (tlab.end() == null)) {