Flex和Java整合错误 [FaultEvent fault=[RPC Fault faultString="Send failed"

第一次按照例子做的FLEX DEMO ,出现如下错误 ,在此记录一下:
[FaultEvent fault=[RPC Fault faultString="Send failed"
faultCode="Client.Error.MessageSend"
faultDetail="Channel.Connect.Failed error NetConnection.Call.Failed:
HTTP: Status 404: url: 'http://localhost:8080/WebContent/messagebroker/amf'"]
messageId="C25D6E12-4A22-9827-849A-C56BBBB434F4" type="fault" bubbles=false
cancelable=true eventPhase=2]

解决方法:
在
<mx:RemoteObject id="firstRO" destination="FirstJavaClassRemoteObject"
fault="faultEvent(event)" endpoint="http://localhost:8080/FlexDemo/messagebroker/amf"/>