diff --git a/jboss-yarn/jboss/src/main/java/org/yarnbook/JBossApplicationMaster.java b/jboss-yarn/jboss/src/main/java/org/yarnbook/JBossApplicationMaster.java
index d251a47..5b0c522 100644
--- a/jboss-yarn/jboss/src/main/java/org/yarnbook/JBossApplicationMaster.java
+++ b/jboss-yarn/jboss/src/main/java/org/yarnbook/JBossApplicationMaster.java
@@ -114,7 +114,7 @@ public class JBossApplicationMaster {
 	private volatile boolean done;
 	private volatile boolean success;
 
-	private List<Thread> launchThreads = new ArrayList<Thread>();
+	private List<Thread> launchThreads = new CopyOnWriteArrayList<Thread>();
 
 	/**
 	 * @param args
@@ -712,4 +712,4 @@ private ContainerRequest setupContainerAskForRM() {
 		LOG.info("Requested container ask: " + request.toString());
 		return request;
 	}
-}
\ No newline at end of file
+}