Only modify threads if allowed to by the environment

Author: michaelklishin

src/com/rabbitmq/client/impl/ChannelManager.java

@@ -116,7 +116,9 @@ public void run() {
             }
         };
         Thread shutdownThread = threadFactory.newThread(target, "ConsumerWorkService shutdown monitor");
-        shutdownThread.setDaemon(true);
+        if(Environment.isAllowedToModifyThreads()) {
+            shutdownThread.setDaemon(true);
+        }
         shutdownThread.start();
     }
 

src/com/rabbitmq/client/impl/Environment.java

@@ -0,0 +1,18 @@
+package com.rabbitmq.client.impl;
+
+/**
+ * Infers information about the execution environment, e.g.
+ * security permissions.
+ */
+class Environment {
+    public static boolean isAllowedToModifyThreads() {
+        SecurityManager sm = new SecurityManager();
+        try {
+            sm.checkPermission(new RuntimePermission("modifyThread"));
+            sm.checkPermission(new RuntimePermission("modifyThreadGroup"));
+            return true;
+        } catch (SecurityException se) {
+            return false;
+        }
+    }
+}