The SAP Java Connector (SAP JCo) is a middleware component that enables the development of SAP-compatible components and applications in Java. SAP JCo supports communication with the SAP Server in both directions: inbound (Java calls ABAP) and outbound calls (ABAP calls Java).
SAP JCo can be implemented with Desktop applications and with Web server applications.
SAP JCo is used as an integrated component in the following applications:
SAP Business Connector, for communication with external Java applications
Application Server, for connecting the integrated Java EE server with the ABAP environment.
SAP JCo can also be implemented as a standalone component, for example to establish communication with the SAP system for individual online (web) applications.
SAP provides SAP Java Connector in a number of different versions:
as a standalone software component that can be installed independently of the SAP system.
Note
Additionally, you can use the IDoc Class Library for IDoc-based communication.
You find the installation files for SAP JCo and the IDoc class library under service.sap.com/connectors.
SAP JCo is automatically installed (integrated version) when you use the SAP Business Connector or AS Java.
The integrated SAP JCo is offered in the current AS Java (release 7.1) with a completely remodified API. This new API corresponds to JCo standalone version 3.0. The old JCo API (corresponding to JCo standalone version 2.x) is also still available in AS Java 7.1.
Note
It is, however, strongly recommended that you use the new API because the old version will probably not be available with the new AS Java release (> 7.1x).
In some respects the old and new JCo API versions differ from each other greatly, particularly with regard to the programming model. For this reason, the client and server programming for SAP JCo is documented separately for both API versions (standalone 2.x, 3.0).
The activities required for upgrading from the old SAP JCo (standalone 2.x) to the new one (standalone 3.0) are described in a separate section on migration.
You should not consider a migration to the new JCo API if you use the integrated SAP JCo in AS Java and the SAP Java environment in both systems involved, consider instead Using SAP Java Resource Adapter (SAP JRA), because this option has considerable advantages for performance and administration.