SAP NetWeaver 7.3
AS Java Introduction
By
Phani Kumar DS
NetWeaver 7.3
• The new version is set to become available at
the start of 2011 and provides a whole range
of revised functions. For example, release 7.3
supports Java EE 5 as well as Enterprise
Service Bus (ESB) for Java. The Java Message
Service (JMS) is also new as a publish-andsubscribe function. Furthermore, SAP
NetWeaver 7.3 supports WS Policy 1.2, SOAP
1.2, WS Trust 1.3, Java SE 6, JSR 168/286,
WSRP 1.0, and SAML 1.0/2.0.
Architecture
The AS Java system consists of three logical layers:
• Java Enterprise Runtime - comprises low-level
subsystems that provide functions such as class
loading, cluster communication, persistent
configuration data management, and so on.
• AS Java System Components - consists of facades,
interfaces, libraries and services components that
provide various runtime functions and
programming APIs.
• Applications - refers to the applications that are
deployed and run on AS Java.
Architecture
Components
The following types of components exist:
• ●
Facades – they simplify the relationships between SAP NetWeaver layers and client
applications. Facades are the only official way for clients to access the AS Java API. They help to
define what is an ‘external (publicly available) API’ and what is an ‘internal API’. Everything that is
part of a facade is public and the client code must be built against it. Everything that is not part of
a facade is not official and the client code should not rely on it. Clients in this context can be
components from other layers of the product and customer applications. If a client needs a
reference to the public API of a certain component (service, interface, or a library), it must
reference the facade which contains the API of the component.
• ● Interfaces – they define how different components of the system work together. At runtime,
they provide the system with their name and classes (no objects). They are used by services
components that provide their implementation.
• ●
Libraries – they provide name, classes and objects to the system. These objects are created
by the system when it loads the library, or when an object is first requested. Libraries are not
active components – they have no definite life cycle, do not allocate resources themselves and do
not keep any kind of configuration information in the system. Other library components or
services components usually access them using static methods.
• ●
Services – they provide the system with their name, classes, and runtime objects. The
runtime objects are registered in the system once the components classes have been loaded.
Service components can access and utilize functions of the runtime through the Framework API.
Services are active components with a definite life cycle. They can allocate resources at their
startup time and are responsible for releasing them at shutdown time.
Features
•
•
•
The AS Java system architecture is based on the following general rule:
components from a higher level can use components from a lower level only
through a set of defined APIs - facades; whereas components from a lower level
are not aware of the APIs of the components from a higher level and therefore
cannot use them.
This rule is reflected by the order of starting the system modules: the runtime is
started first, then the services (the libraries are loaded, the interfaces resolved at
this phase), and the applications are started last. The system is considered as
started when all runtime managers and core services components are started
properly.
The AS Java system components use the Framework APIs to connect to the Java
enterprise runtime. Applications use the AS Java system components using the
APIs that are defined by Java EE 5 specification (and supporting specifications) and
SAP-proprietary APIs.
Standard SAP Java System Based on SAP NetWeaver 7.2 and Higher
Standard SAP Dual-Stack (ABAP+Java) System Based on SAP NetWeaver 7.2 and Higher
Additional Application Server Instance (Dialog Instance)
Dual-stack (ABAP+Java) system
AS Java Cluster Architecture
Central services instance
• The central services instance consists of a
Message Service and Enqueue Service. They
are responsible for lock administration,
message exchange and load balancing within
the Java cluster.
One or more Java instances
• A Java instance consists of an Internet
Communication Manager (ICM) and one or
several server processes. The ICM handles
Minimum AS Java Cluster
Installation
Large AS Java Cluster Installation
Load Balancing in AS Java
Load Balancing Among Java Instances
• There is a central load balancer, which lies
between the Internet and your system and
serves as the entry point for all user requests. For
this purpose, you can use the SAP Web
dispatcher. It is a standalone program that
distributes incoming Web requests (HTTP, HTTPS)
evenly among the Java instances within your AS
Java cluster.
• If the request is coming from an external client
over a remote protocol (RMI-P4), it either goes to
The Startup Framework for AS
Java
The Startup Framework provides the following
services:
• It serves as a single point of administration
(starting, restarting, stopping, and monitoring)
for the AS Java processes.
• In case of a process failure, it restarts the
corresponding process.
• It displays the trace files, the system
environment,
and
the
SAP
system
environment.
Architecture of the Java Startup
Framework
JSTART
The Java Startup Framework is implemented in
the JSTART program.
The JSTART program has two roles:
• When running as the Java instance controller,
JSTART starts, stops, and monitors the
processes of a Java instance (the ICM process
and several Java server processes). In this role,
JSTART provides a local port for command
communication and implements the SAP
signal handling to stop the instance.
• In the role of a server process, JSTART
Integration
• In an ABAP+Java instance, the ABAP
dispatcher calls the JSTART program.
• In a pure AS Java installation, the following
distinction applies:
– Under Windows, the SAP Start Service calls JSTART
to start an AS Java instance.
– Under UNIX and OS/400 platforms, the SAP Start
Service uses the startsap and stopsap scripts to
call the JSTART program.
Startup of the Java Instance
Startup of the Java Instance
1) JSTART is started (in Windows by the SAP Start Service; on UNIX platforms by the
startsap script). It takes the role of the Java instance controller.
2) The Java instance controller analyzes its configuration (from the instance profile) and
examines the details of the Java SDK defined there.
3) The Java instance controller initializes SAP signal handling to be able to receive signals
and opens the control port.
4) The Java instance controller reads the instance description (from the list of files
specified by the jstart/startupNodeFiles and jstart/instanceNodeFiles profile
parameters) for the first time, searching for nodes with a runLevel=1 property. The
OFFLINE DEPLOYMENT node in the startup.properties file matches this criterion.
5) The Java instance controller starts another JSTART process with the parameters from
the OFFLINE DEPLOYMENT node and waits for the child process to terminate.
6) The child process acts as a Java process. It loads the Java Virtual Machine (JVM) into
its own process, initializes the JVM and starts the OFFLINE DEPLOYMENT program,
which performs the deployment steps in the Java database.
Startup of the Java Instance
7) The Java instance controller reads the instance description again, searching for nodes
with a runLevel=2 property. The BOOTSTRAP node in the startup.properties file meets
this condition.
8) The Java instance controller starts another JSTART process with the parameters from
the BOOTSTRAP node and waits for the child process to terminate.
9) The child process loads and initializes the JVM and starts the BOOTSTRAP program.
BOOTSTRAP synchronizes the binary data in the Java database with the local file system,
reads the Java instance description from the Java database and updates the
instance.properties file.
10) The Java instance controller reads the instance description from the startup.properties
and instance.properties files once more, this time focusing on nodes with a runLevel=3
property or without a runLevel property at all. These nodes form the productive
instance.
11) The Java instance controller starts the processes for infrastructure nodes, such as ICM
or DEBUGPROXY.
12) When all infrastructure processes are started, the Java instance controller starts the
processes for the server nodes.
13) The JSTART child processes act as Java processes and execute a similar sequence as
described before. They become the Java server processes.
Shutdown of the Java Instance
Shutdown of the Java Instance
• An instance is stopped as follows:
• A process (for example, the ABAP dispatcher, a
start script or SAP Start Service) sends a
SIGINT signal or an appropriate command to
the Java instance controller.
• The Java instance controller updates the
instance state and sends STOP commands to
the server processes.
• When the server processes are finished, the
Java instance controller sends STOP
Administration of the Java Startup
Framework
• Administration and monitoring with the SAP
Management Console
• Administration and monitoring with the
command line program jsmon
• Monitoring and interpreting the trace and log
files created by the framework, analyzing the
error
messages
in
them,
incrementing/decrementing the trace levels,
Using the Command Line Program
jsmon
Prerequisites
• The AS Java instance is running.
• You are logged on at operating system level
to the computer where the AS Java instance
is running. In the following <profile> refers to
the name of the profile file with which the
Java instance controller was started.
Procedure
• Call jsmon pf=<path to profile> from the
command line.
• The JStart Monitor Program is started. Some
Developer Trace and Log Files
•
The developer trace and log files are located in the /usr/sap/SID/inst_name/work
directory
dev_jstart
• This is the trace file of the Java instance controller.
dev_<component name>
• The trace file of the corresponding JSTART server process (the <component name>
can be deployment, bootstrap, server<n>, or icm). For example, the trace file for the
bootstrap process is dev_bootstrap.
std_<component name>.out
• The standard and error output file of the corresponding JSTART server process (the
<component name> can be deployment, bootstrap, server<n>, or icm).
jvm_<component name>.out
• The standard and error output file of the JVM running the corresponding JSTART
server process (the <component name> can be deployment, bootstrap, or server<n>).
Configuration of the Java Startup
Framework
Command line arguments for the Java Instance Controller
SAP Instance Profile
•
The SAP instance profile that contains all properties related to the AS Java instance. This file is normally created by
SAPinst and contains the SAP instance properties, such as SAPSYSTEM (system number) or SAPSYSTEMNAME (system
ID), and so on.
•
Program argument: pf=<filename>
•
Internal default value: this parameter is mandatory; there is no default value
Bootstrap Mode
•
This option allows you to skip the offline deployment and bootstrap phases when the Java instance is started.
•
Program argument: -bootstrap=[yes/no]
•
SAP profile property: jstart/bootstrap = [yes/no]
•
Internal default value: yes
Trace Level
•
The trace level is configured in the instance profile; it can be overridden for the Java instance controller with this
argument.
•
Program argument: -tracelevel=[0..3]
•
SAP profile property: jstart/TRACE = [0..3] or rdisp/TRACE = [0..3]
•
Internal default value: 1
Special Command Line Arguments
•
The following command line arguments are used by the JSTART processes to configure the runtime behavior or to tune
some specific properties and options.
•
Note: You cannot use these command line arguments to configure the Java Startup Framework. These arguments are
documented here for trace file analysis only.
Special Command Line Arguments
Shared Memory Node ID
•
The Java instance uses shared memory for administration, monitoring and session management. Each process that accesses this
shared memory needs a node ID that identifies the process and assigns a part of the shared memory for status reporting.
•
Program argument: -nodeId=<shared memory ID>
•
Internal default value: -1 (no relation to a shared memory segment)
Java System Properties
•
The Java VM provides a set of system properties, which can be extended during Java VM initialization. This command line
argument is added to the initial set of Java system properties. It may occur several times with different <name>=<value> pairs.
•
Program argument: -hostvm
•
Internal default value: —D<name>=<value>
Operation Mode
•
The JSTART program can operate in three different modes: Java instance controller, Java launcher, or host process for a Java VM.
This argument assigns the Java VM host mode.
•
Program argument: -hostvm
•
Internal default value: depends on the presence of several other command line arguments if the mode is not explicitly assigned
Node Name
•
The node name specifies the section in the node definition file that defines the node. This (technical) name may differ from the
(visible) name of the node in the trace file and the management UIs
•
Program argument: -nodeName=<node name>
•
Internal default value: none
Node Definition File
•
This file contains the parameters for the node being represented by the JSTART process.
•
Program argument: -file=<file name>
•
Internal default value: none
Special Command Line Arguments
Java SDK Configuration File
•
When JSTART operates as a Java instance controller or Java launcher, it analyzes the Java SDK defined in the node definition and instance
profile. It then stores the results in the Java SDK configuration file and shares them with the Java host processes.
•
Program argument: -jdkFile=<file name>
•
Internal default value: none
Developer Trace File
•
The name of the developer trace file. More information: Developer Trace and Log Files.
•
Program argument: -traceFile=<file name>
•
Internal default value: none, trace messages are written to the standard output stream
Detailed Protocol in the Trace File
•
This option controls the output of the command line options and arguments passed to the child processes, Java VM and Java main method.
•
Program argument: -protocol=[on/off]
•
Internal default value: jstart/protocol
Java VM Output Redirection
•
This option allows you to redirect the standard and error output of the Java VM to a specified file.
•
Program argument: -jvmOutFile=<file name> or -javaOutFile=<file name>
•
Internal default value: none
Activate Debug Mode
•
This option activates Java debugging with the debugging agent. It is used to enable debugging with Java VMs from other vendors
•
Program argument: -debugMode=[yes/no]
•
SAP profile property: jstart/debugMode
•
Internal default value: no
Additional Environment Settings
•
This option allows you to add environment settings to JSTART. The value has to be in the format: envvar1=value;envvar2=value;…
•
Program argument: -environment=<list of environment variables>
•
SAP profile property: jstart/environment
•
Internal default value: none
SAP Profile Parameters
• The instance profile contains the important
SAP profile parameters used by the JSTART
program. These parameters apply to the
whole AS Java instance. The file is located in
/usr/sap/<SID>/SYS/profile/<SID>_<instance
name>_<hostname>.
SAP Profile Parameters
Profile Parameter
(old name in parantheses)
Description
Unit
Default Value
jstart/bootstrap
(jstartup/bootstrap)
Controls whether the initial
offline deployment and
bootstrap phases happen when
an AS Java instance starts.
Logical value
True
jstart/protocol
(jstartup/protocol)
Activates additional protocol
output in the developer trace
file.
Logical value
True
jstart/debuggable
(jstartup/debuggable)
Protects an instance against
debugging, e.g. for productive
use.
Logical value
True
jstart/debug_mode
(jstartup/debug_mode)
Activates Java debugging for
all server processes. A Java
VM in debugging mode is
extremely slow. When using
the SAP JVM, debugging can
be activated if necessary, i.e.
“on the fly”.
Logical value
false
jstart/environment
(jstartup/environment)
May contain additional
environment variables that are
passed by the instance
controller to the Java
processes.
Character string
SAP Profile Parameters - 1
jstart/startupNodeFile
(jstartup/startup_properties)
Specifies the name of the file that
contains the node definitions
for the bootstrap and offline
deployment phases.
Note:Do not change the value of
this parameter.
Character string
$(DIR_EXECUTABLE)/startup.prop
erties
jstart/instanceNodeFiles
(jstartup/instance_properties)
Provides the list of files defining
the nodes that build the
instance.
Note: Do not change the value of
this parameter.
Character string
<computed at runtime>
jstart/stackSize
(jstartup/native_stack_size)
Stack size (in bytes) for the Java
VM thread.
Whole number; may contain
k, m or g as scaling
factors.
The value is platformdependent. It is 256k on
32-bit platforms, 1m on
64-bit Unix platforms, and
2m on 64-bit Windows
platforms.
jstart/vm/home
(jstartup/vm/home)
Path to the root directory of the
Java SDK
Character string
$(DIR_SAPJVM)
jstart/vm/type
jstartup/vm/type
Java VM type (for example, server,
classic, or client).
The values are vendor-specific –
refer to the Java VM vendor’s
documentation.
Character string
SAP Profile Parameters - 2
jstart/vm/args
(jstartup/vm/parameters)
Additional VM parameters for all
nodes (for example,
DsomeName=someValue)
Character string
jstart/vm/libPath
(jstart/vm/libpath)
Specifies a list of directories
containing shared libraries.
If this parameter is set, its value
overrides the directories found
during Java SDK detection.
Character string
jstart/vm/dllname
(jstartup/vm/dllname)
File name of the Java VM shared
library (if the library name is
not “jvm”).
This parameter can be used to run a
debug version of the Java VM
that has a different file name.
Character string
jstart/nice
(jstartup/nice)
Allows you to run the node
processes at lower priority, e.g.
on desktop systems.
This feature is available only on
Windows.
Logical value
DIR_EXECUTABLE
Directory where the executable files
for the startup framework are
located.
Character string
SAPSYSTEMNAME
SAP system name. (SID)
Character string with
three characters
false
SAP Profile Parameters - 3
SAPSYSTEM
SAP instance number.
Whole number (between 00
and 97)
jstart/TRACE
Specifies the trace level for
the information logged
in the developer trace
files.
Whole number (between 0
and 3)
jstart/TRACE_COMPS
Specifies the trace
components that may
trace at a higher trace
level.
Character string consisting of
letters for the trace
components and the
strings All or all.
Restricts the size of the
developer traces.
Character string with the
following syntax: off | on,
Specifies the number of
backup versions for
trace and log files.
The JSTART program
replaces the last one or
two digits of the
extension with the
backup generation or
appends an “.n”
extension to files that
have no extension.
Whole number (between 0
and 99)
jstart/TRACE_LOGGING
jstart/traceVersions
(jstartup/keep_old_logfiles)
Value of the rdisp/TRACE
parameter.
Value of the
rdisp/TRACE_COMPS
parameter
The value of the
rdisp/TRACE_LOGGING
<n> [ k | m ]
parameter
5
SAP Profile Parameters - 4
jstart/shutdownTimeout
(jstartup/shutdown_timeout)
Specifies the shutdown
timeout, i.e. the grace
period for the AS Java
instance to shut down
before the Java process
terminates itself.
Seconds
120
j2ee/ms/connectTimeout
(jstartup/wait_for_scs)
Specifies the timeout for the
first connection to the
message server.
The AS Java instance fails to
start if this timeout
expires.
Seconds
60
j2ee/ms/reconnectTimeout
(jstartup/wait_for_reconnect)
Specifies the timeout for the
reconnecting to the
message server.
The AS Java instance shuts
down when this timeout
expires.
Seconds
3600 (one hour)
For Further Info
http://help.sap.com/saphelp_nwce71core/help
data/en/e1/b5443e02a9ab4186a6e1240a9a2
455/frameset.htm