Administration of Client Programs 
This section contains information about client programs that are used by (many) users on their local PCs to access functions of SAP NetWeaver systems or standalone engines in the landscape. The following client programs exist:
The J2SE Adapter Engine is a standalone software tool that you can only use in connection with SAP NetWeaver systems that are operated in the Usage Type PI.
You can use the J2SE Adapter Engine to communicate with external systems. However, it only offers restricted functions compared to the J2EE-based Adapter Engine and should therefore only be used if your system environment does not support the use of the J2EE Adapter Engine.