As mentioned previously, the gateway is the component which lives on the server and is responsible for converting object instances between java and ActionScript. It can carry out deep copies and knows which java objects map to your Actionscript objects, assuming you have marked them with

[RemoteClass(alias="java.package.structure.classname")]

We can change the log level of the gateway and take a look at what it is up to.

In services-config.xml, change the log level from Error to Debug as below:

   <logging>

      <target class="flex.messaging.log.ConsoleTarget" level="Debug">

You will now have to restart JBoss. Now load up the app in your browser, also have the JBoss console on your screen, enter an address into the form and submit.
You will see the output of the 'request' in the console:

The output below occurs the first time a call is made from the client, it's just checking that the endpoint is still available, don't expect to see this every call.

12:16:14,805 INFO  [STDOUT] [Flex] Deserializing AMF/HTTP request

Version: 3

  (Message #0 targetURI=null, responseURI=/1)

    (Array #0)

      [0] = (Typed Object #0 'flex.messaging.messages.CommandMessage')

        operation = 5

        messageRefType = null

        correlationId = ""

        messageId = "8DA9ED25-7DA2-0175-16F8-5D4D2EF8E163"

        headers = (Object #1)

        timestamp = 0

        body = (Object #2)

        clientId = null

        destination = ""

        timeToLive = 0

12:16:14,837 INFO  [STDOUT] [Flex] Serializing AMF/HTTP response

Version: 3

  (Message #0 targetURI=/1/onResult, responseURI=)

    (Typed Object #0 'flex.messaging.messages.AcknowledgeMessage')

      destination = null

      headers = (Object #1)

      correlationId = "8DA9ED25-7DA2-0175-16F8-5D4D2EF8E163"

      messageId = "2FC970B5-9518-4649-21E9-ED57D3A627EC"

      timestamp = 1.152616574821E12

      clientId = "2FC970B5-950E-1903-993A-5EB4299C54B5"

      timeToLive = 0.0

      body = null

Next you will see our request to the remote object:

12:16:14,852 INFO  [STDOUT] [Flex] Channel endpoint my-amf received request.

12:16:14,868 INFO  [STDOUT] [Flex] Deserializing AMF/HTTP request

Version: 3

  (Message #0 targetURI=null, responseURI=/2)

    (Array #0)

      [0] = (Typed Object #0 'flex.messaging.messages.RemotingMessage')

        operation = "addAddress"

        source = null

        messageId = "D9F1547F-D5A7-4C11-E53D-5D4D2ED818F1"

        headers = (Object #1)

          DSEndpoint = "my-amf"

        timestamp = 0

        body = (Array #2)

          [0] = (Typed Object #3 'fdsweb.AddressVO')

            line2 = "The Street"

            line1 = "44"

            postalCode = "EH11 9DQ"

            city = "EDINBURGH"

        clientId = null

        destination = "addressBookDelegate"

        timeToLive = 0

Remember that the data does not get transmitted in textual format, it gets sent in binary AMF, this is just the output from the gateway logging after it has received it.

Next we see the gateway calling the remote object and the results from that call:

12:16:14,868 INFO  [STDOUT] [Flex] Adapter 'java-object' called 'fdsweb.AddressB
ookDelegate.addAddress(java.util.Arrays$ArrayList (Collection size:1)
  [0] = fdsweb.AddressVO
    postalCode = EH11 9DQ
    line1 = 44
    line2 = The Street
    city = EDINBURGH

)'

12:16:14,868 INFO  [STDOUT] [Flex] Result: 'java.util.Vector (Collection size:1)


  [0] = fdsweb.AddressVO

    postalCode = EH11 9DQ

    line1 = 44

    line2 = The Street

    city = EDINBURGH

)'

And finally we see the response about to go back to the client:

12:16:14,868 INFO  [STDOUT] [Flex] Serializing AMF/HTTP response
Version: 3
  (Message #0 targetURI=/2/onResult, responseURI=)
    (Typed Object #0 'flex.messaging.messages.AcknowledgeMessage')
      destination = null
      headers = (Object #1)
      correlationId = "D9F1547F-D5A7-4C11-E53D-5D4D2ED818F1"
      messageId = "2FC97128-541C-9D37-38F6-21D302743239"
      timestamp = 1.152616574868E12
      clientId = "2FC97128-540D-3181-BC10-60C5D327A94E"
      timeToLive = 0.0
      body = (Externalizable Object #2 'flex.messaging.io.ArrayCollection')
        (Array #3)
          [0] = (Typed Object #4 'fdsweb.AddressVO')
            postalCode = "EH11 9DQ"
            line1 = "44"
            line2 = "The Street"
            city = "EDINBURGH"

The flex debugging provided in Eclipse is very similar to the java debugging and is intuitive for anyone who has ever used the java debugger. For the full details on debugging in Flex Builder, see the docs, for now you are good to go if you can just set a breakpoint as in the java debugger.

If you want to debug the remote object running in JBoss, you can set up JPDA (Java Platform Debugger Architecture). This allows Eclipse to connect to JBoss by way of sockets and exchange debugging information necessary for the java debugger.

Setting up JPDA in JBoss is actually very simple, all you need to do is:

a) stop JBoss
b) copy the [jboss root]/bin/run.bat to [jboss root]/bin/run_debug.bat (Unix/Linux users change as necessary)
c) in run_debug.bat, uncomment this line:

rem JPDA options. Uncomment and modify as appropriate to enable remote debugging.

rem set JAVA_OPTS=-Xdebug -Xrunjdwp:transport=dt_socket,address=8787,server=y,suspend=y %JAVA_OPTS%

to read this:

rem JPDA options. Uncomment and modify as appropriate to enable remote debugging.

set JAVA_OPTS=-Xdebug -Xrunjdwp:transport=dt_socket,address=8787,server=y,suspend=y %JAVA_OPTS%

d) start JBoss using your new run_debug script
e) in Flexbuilder/Eclipse, click on the 'bug' icon and select 'Debug....'
f) select 'Remote Java Application' and hit 'new', change the name of the configuration if you wish, change the port to 8787 (or change the connection properties to reflect those set in the run_debug script if different from above).
g) click debug
h) in the AddressBookDelegate source, add a breakpoint in the addAddress method
i) open the app in your browser and submit an address, you may need to press 'continue' if you do not reach the breakpoint straight away.

From the above techniques, you should be able to set a breakpoint in the Flex code and the java code and watch the gateway debug output, this will give you end to end debugging.