Components of SAP NetWeaver Application Server Java

SAP NetWeaver Application Server can be installed in various specifications depending on the SAP product and applications used. A distinction is made between ABAP systems, Java systems, and dual-stack systems. Depending on the SAP product used, not every specification may be available. The components of an AS Java are listed below. Optional components, such as SAP Web Dispatcher, are listed too.

Overview of the Components of SAP NW AS Dual Stack

Component	Description
Internet Communication Manager (ICM)	Application server component that receives and dispatches Web requests (HTTP(S), SMTP,…). ICM evaluates the URL and forwards requests to AS ABAP or AS Java accordingly.
SAP Web Dispatcher	Standalone program installed in the DMZ (demilitarized zone) that acts as a point of entry for Web requests. Web Dispatcher balances the load across the application servers and can also perform other monitoring tasks.
SAP Message Server	Only one message server can run in each SAP system. It performs the following tasks in the SAP system: Central communication channel between the individual application servers (instances) of the system Load distribution of logons using SAP GUI and RFC with logon groups Information point for the Web Dispatcher and the application servers (each application server of the system firsts logs on to the message server)
Standalone enqueue server	Part of the central instance (ABAP or Java) that manages the SAP locks. In combination with the enqueue replication server, this single point-of-failure can be made into a high availability solution.
SAP Start Service	The SAP start service provides the following functions for monitoring SAP systems, instances, and processes. Starting and stopping Monitoring the runtime state Reading logs, traces, and configuration files Technical information, such as network ports, active sessions, thread lists, etc.
Java Startup and Control Framework	The Java startup and control framework is used to start, stop, and monitor a Java Instance. The Java startup and control framework consists of the JControl and JLaunch programs. JLaunch is started by JControl, and JLaunch itself starts the bootstrap Java program or an element of the Java cluster (dispatcher or server process).
Java Server Process	The server processes of the J2EE Engine execute the J2EE application. Each server process is multi-threaded, and can therefore run multiple requests in parallel.