1 files changed, 30 insertions, 0 deletions
diff --git a/vespajlib/src/main/java/com/yahoo/concurrent/Threads.java b/vespajlib/src/main/java/com/yahoo/concurrent/Threads.java
new file mode 100644
index 00000000000..d30750692e9
--- /dev/null
+++ b/vespajlib/src/main/java/com/yahoo/concurrent/Threads.java
@@ -0,0 +1,30 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.concurrent;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+
+/**
+ * @author bjorncs
+ */
+public class Threads {
+
+    private Threads() {}
+
+    /** Returns all threads in JVM */
+    public static Collection<Thread> getAllThreads() {
+        ThreadGroup root = Thread.currentThread().getThreadGroup();
+        ThreadGroup parent;
+        while ((parent = root.getParent()) != null) {
+            root = parent;
+        }
+        // The number of threads may increase between activeCount() and enumerate()
+        Thread[] threads = new Thread[root.activeCount() + 100];
+        int count;
+        while ((count = root.enumerate(threads, true)) == threads.length) {
+            threads = new Thread[threads.length + 1000];
+        }
+        return List.of(Arrays.copyOf(threads, count));
+    }
+}