This framework provides ISO8583 messaging utilities for Java 5. Its objective is to simplify as much as possible the creation and parsing of ISO8583 messages.
The message format and protocol are somewhat complex and cumbersome. The definition is available here so we will not be getting into the protocol specification. This document and the framework are intended for people who are already familiar with this standard.
UPDATE: Due to popular demand, I have included a brief description of the protocol, both in English and Spanish.
You can download the framework here.
It includes documentation and some examples using TCP sockets which is the typical means of communication using this protocol.
Configuring j8583 is very easy. You can create a XML configuration file and place it in a file inside the classpath. The default is j8583.xml in the classpath root. The configuration file can contain definitions for ISO headers, message templates and parsing guides. The DTD is located here if you want to take a look at it or use it with a XML editor.
You use the ConfigParser to create a MessageFactory and configure it with a XML file. Once you have a MessageFactory you only need to specify whether you want it to set the date on newly created messages, and also set a TraceNumberGenerator to set the trace number for newly created messages.
You can learn how to use the XML configuration here.
You can also check the online API Documentation.
Breve explicación del protocolo ISO-8583