How to send file in Android with Asmack+Openfire?

could you please send me the code to send file using Asmack + openfire.
I tried, but I am getting error like error code="503" type="cancel.
Please, help me.

Solution

You have to send a fully-qualified jabber ID as detination userID when you create the OutgoingFileTransfer it consists of a node, a domain, and a resource (user@domain/resource) as I said before in the comments, actually you are sending a2@aaa and is not correct.

<iq id="SU8c1-17" to="a2@aaa" from="a1@aaa/Smack" type="set">
    <si xmlns="http://jabber.org/protocol/si" id="jsi_2427513438410796738" profile="http://jabber.org/protocol/si/profile/file-transfer">
        <file xmlns="http://jabber.org/protocol/si/profile/file-transfer" name="user.json" size="379">
            <desc>test_file</desc>
        </file>
        <feature xmlns="http://jabber.org/protocol/feature-neg">
            <x xmlns="jabber:x:data" type="form">
                <field var="stream-method" type="list-multi">
                    <option>
                        <value>http://jabber.org/protocol/bytestreams</value>
                    </option>
                    <option>
                        <value>http://jabber.org/protocol/ibb</value>
                    </option>
                </field>
            </x>
        </feature>
    </si>
</iq>

So, your sentTo variable shoulbe

String sentTo = "user@domain/resource";

OutgoingFileTransfer transfer = manager.createOutgoingFileTransfer(sentTo)