Managing Serviceguard Extension for SAP, December 2007

Understanding Serviceguard Extension for SAP
Clustering Stand-Alone J2EE Components
Chapter 124
A one-package setup for pure JAVA environments implements a
jdbjciSID package.
The jdb package type becomes necessary in addition to the db package
type since in SAP JAVA environments different database tools are
common than in ABAP environments. SGeSAP follows the JAVA
approach for jdb packages and the ABAP-world treatment for db
packages.
Even if they are installed in combination with ABAP instances, some
SAP JAVA components can require a separate database instance. For
this case, SGeSAP allows to specify one package that contains a db and
another package that contains a jdb component.
NOTE It is not allowed to specify a single SGeSAP package with two database
instances in it. An environment with db and jdb requires at least two
packages to be defined.
The jci package type is always dedicated to a JAVA System Central
Service (SCS) Instance. The implementation of JAVA System Central
Services is not written in JAVA. It uses stand-alone Enqueue and
Message Server implementations similar to the ones delivered with
ABAP kernels.