Index: core/src/main/scala/kafka/server/KafkaConfig.scala
===================================================================
--- core/src/main/scala/kafka/server/KafkaConfig.scala	(revision 1372703)
+++ core/src/main/scala/kafka/server/KafkaConfig.scala	(working copy)
@@ -33,6 +33,7 @@
 
   /* the broker id for this server */
   val brokerId: Int = Utils.getInt(props, "brokerid")
+  require(brokerId >= 0, "The broker Id must be non-negative.")
   
   /* the SO_SNDBUFF buffer of the socket sever sockets */
   val socketSendBuffer: Int = Utils.getInt(props, "socket.send.buffer", 100*1024)