From fb300c873102a669767ddc9f624efd0353b77b34 Mon Sep 17 00:00:00 2001
From: Christian Basler <chrigu.meyer@gmail.com>
Date: Mon, 19 Oct 2015 15:08:11 +0200
Subject: [PATCH] Fixed possible ConcurrentModificationException

---
 .../ch/dissem/bitmessage/ports/MultiThreadedPOWEngine.java    | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/domain/src/main/java/ch/dissem/bitmessage/ports/MultiThreadedPOWEngine.java b/domain/src/main/java/ch/dissem/bitmessage/ports/MultiThreadedPOWEngine.java
index 3c4572e..a4f02f5 100644
--- a/domain/src/main/java/ch/dissem/bitmessage/ports/MultiThreadedPOWEngine.java
+++ b/domain/src/main/java/ch/dissem/bitmessage/ports/MultiThreadedPOWEngine.java
@@ -43,6 +43,10 @@ public class MultiThreadedPOWEngine implements ProofOfWorkEngine {
         for (int i = 0; i < cores; i++) {
             Worker w = new Worker(workers, (byte) cores, i, initialHash, target);
             workers.add(w);
+        }
+        for (Worker w : workers) {
+            // Doing this in the previous loop might cause a ConcurrentModificationException in the worker
+            // if a worker finds a nonce while new ones are still being added.
             w.start();
         }
         for (Worker w : workers) {