With NetWeaver 7.1 and JCO 3.0, SAP has completely integrated Java connectivity within the SAP Web Application Server. As such, knowledge of standalone JCO clients has become less valuable. However, there remains a great deal of work within specific SAP technology stacks. If you are more interested in Web applications and user-facing development, check out WebDynpro for Java or simply the NetWeaver Portal development toolkit provided with NetWeaver Developer Studio.
If you are interested in middleware connectivity, connecting SAP to non-SAP systems, or more broadly the enterprise service bus (service-oriented architecture (SOA)), then focus on SAP XI. XI provides XML-based communication between disparate systems, with JCO as the underlying Java communications connector.
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