diff --git a/.jenkins/Jenkinsfile b/.jenkins/Jenkinsfile
index fd4aa64c29..163968934e 100644
--- a/.jenkins/Jenkinsfile
+++ b/.jenkins/Jenkinsfile
@@ -434,6 +434,11 @@ def test(command, cell) {
             if (!cell.step.startsWith("microbench")) {
               junit testResults: "test/**/TEST-*.xml,test/**/cqlshlib*.xml,test/**/nosetests*.xml", testDataPublishers: [[$class: 'StabilityTestDataPublisher']]
             }
+            // check if we had Linux OOM killer active within the test container which could kill forked JUnit JVM processes
+             sh """
+                echo "docker memory/oomkiller debug:"
+                cat /sys/fs/cgroup/docker/memory.events || true
+              """
             sh """
                 find test/output -type f -name "*.xml" -print0 | xargs -0 -r -n1 -P"\$(nproc)" xz -f
                 echo "test result files compressed"; find test/output -type f -name "*.xml.xz" | wc -l
diff --git a/test/unit/org/apache/cassandra/JStackJUnitTask.java b/test/unit/org/apache/cassandra/JStackJUnitTask.java
index 69480a6a47..334525992b 100644
--- a/test/unit/org/apache/cassandra/JStackJUnitTask.java
+++ b/test/unit/org/apache/cassandra/JStackJUnitTask.java
@@ -20,7 +20,6 @@ package org.apache.cassandra;
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStreamReader;
-import java.lang.reflect.Field;
 
 import org.apache.tools.ant.BuildException;
 import org.apache.tools.ant.taskdefs.ExecuteWatchdog;
@@ -77,6 +76,7 @@ public class JStackJUnitTask extends JUnitTask
                 ProcessBuilder pb = new ProcessBuilder("jstack","-l", String.valueOf(pid));
                 try
                 {
+                    pb.redirectErrorStream(true);
                     Process p = pb.start();
                     try (BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream())))
                     {
@@ -100,22 +100,15 @@ public class JStackJUnitTask extends JUnitTask
 
         private long getPid(Process process)
         {
-            if (process.getClass().getName().equals("java.lang.UNIXProcess"))
+            try
             {
-                try
-                {
-                    Field f = process.getClass().getDeclaredField("pid");
-                    f.setAccessible(true);
-                    long pid = f.getLong(process);
-                    f.setAccessible(false);
-                    return pid;
-                }
-                catch (IllegalAccessException | NoSuchFieldException e)
-                {
-                    System.err.println("Could not get PID");
-                }
+                return process.pid();
+            }
+            catch (UnsupportedOperationException e)
+            {
+                System.err.println("Could not get PID");
+                return -1;
             }
-            return -1;
         }
     }