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  • TADM10_1SAP NetWeaver AS

    Implementation & OperationI

    SAP NetWeaver

    Date

    Training Center

    Instructors

    Education Website

    Participant HandbookCourse Version: 99Course Duration: 10 Day(s)Material Number: 50118031

    An SAP course - use it to learn, reference it for work

  • Copyright

    Copyright 2013 SAP AG or an SAP affiliate company. All rights reserved.

    No part of this publication may be reproduced or transmitted in any form or for any purpose without theexpress permission of SAP AG. The information contained herein may be changed without prior notice.

    Some software products marketed by SAP AG and its distributors contain proprietary softwarecomponents of other software vendors.

    Trademarks

    Adobe, the Adobe logo, Acrobat, PostScript, and Reader are trademarks or registered trademarks ofAdobe Systems Incorporated in the United States and other countries.

    Apple, App Store, FaceTime, iBooks, iPad, iPhone, iPhoto, iPod, iTunes, Multi-Touch, Objective-C,Retina, Safari, Siri, and Xcode are trademarks or registered trademarks of Apple Inc.

    Bluetooth is a registered trademark of Bluetooth SIG Inc.

    Citrix, ICA, Program Neighborhood, MetaFrame now XenApp, WinFrame, VideoFrame, and MultiWinare trademarks or registered trademarks of Citrix Systems Inc.

    Computop is a registered trademark of Computop Wirtschaftsinformatik GmbH.

    Edgar Online is a registered trademark of EDGAR Online Inc., an R.R. Donnelley & Sons Company.

    Facebook, the Facebook and F logo, FB, Face, Poke, Wall, and 32665 are trademarks of Facebook.

    Google App Engine, Google Apps, Google Checkout, Google Data API, Google Maps, Google MobileAds, Google Mobile Updater, Google Mobile, Google Store, Google Sync, Google Updater, GoogleVoice, Google Mail, Gmail, YouTube, Dalvik, and Android are trademarks or registered trademarks ofGoogle Inc.

    HP is a registered trademark of the Hewlett-Packard Development Company L.P.

    HTML, XML, XHTML, and W3C are trademarks, registered trademarks, or claimed as generic termsby the Massachusetts Institute of Technology (MIT), European Research Consortium for Informaticsand Mathematics (ERCIM), or Keio University.

    IBM, DB2, DB2 Universal Database, System i, System i5, System p, System p5, System x, System z,System z10, z10, z/VM, z/OS, OS/390, zEnterprise, PowerVM, Power Architecture, Power Systems,POWER7, POWER6+, POWER6, POWER, PowerHA, pureScale, PowerPC, BladeCenter, SystemStorage, Storwize, XIV, GPFS, HACMP, RETAIN, DB2 Connect, RACF, Redbooks, OS/2, AIX,Intelligent Miner, WebSphere, Tivoli, Informix, and Smarter Planet are trademarks or registeredtrademarks of IBM Corporation.

    Microsoft, Windows, Excel, Outlook, PowerPoint, Silverlight, and Visual Studio are registeredtrademarks of Microsoft Corporation.

    INTERMEC is a registered trademark of Intermec Technologies Corporation.

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    The Klout name and logos are trademarks of Klout Inc.

    Linux is the registered trademark of Linus Torvalds in the United States and other countries.

    Motorola is a registered trademark of Motorola Trademark Holdings LLC.

    Mozilla and Firefox and their logos are registered trademarks of the Mozilla Foundation.

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  • Novell and SUSE Linux Enterprise Server are registered trademarks of Novell Inc.

    OpenText is a registered trademark of OpenText Corporation.

    Oracle and Java are registered trademarks of Oracle and its affiliates.

    QR Code is a registered trademark of Denso Wave Incorporated.

    RIM, BlackBerry, BBM, BlackBerry Curve, BlackBerry Bold, BlackBerry Pearl, BlackBerry Torch,BlackBerry Storm, BlackBerry Storm2, BlackBerry PlayBook, and BlackBerry AppWorld are trademarksor registered trademarks of Research in Motion Limited.

    SAVO is a registered trademark of The Savo Group Ltd.

    The Skype name is a trademark of Skype or related entities.

    Twitter and Tweet are trademarks or registered trademarks of Twitter.

    UNIX, X/Open, OSF/1, and Motif are registered trademarks of the Open Group.

    Wi-Fi is a registered trademark of Wi-Fi Alliance.

    SAP, R/3, ABAP, BAPI, SAP NetWeaver, Duet, PartnerEdge, ByDesign, SAP BusinessObjects Explorer,StreamWork, SAP HANA, the Business Objects logo, BusinessObjects, Crystal Reports, CrystalDecisions, Web Intelligence, Xcelsius, Sybase, Adaptive Server, Adaptive Server Enterprise, iAnywhere,Sybase 365, SQL Anywhere, Crossgate, B2B 360 and B2B 360 Services, m@gic EDDY, Ariba, theAriba logo, Quadrem, b-process, Ariba Discovery, SuccessFactors, Execution is the Difference, BizXMobile Touchbase, It's time to love work again, SuccessFactors Jam and BadAss SaaS, and other SAPproducts and services mentioned herein as well as their respective logos are trademarks or registeredtrademarks of SAP AG in Germany or an SAP affiliate company.

    All other product and service names mentioned are the trademarks of their respective companies. Datacontained in this document serves informational purposes only. National product specifications may vary.

    Disclaimer

    These materials are subject to change without notice. These materials are provided by SAP AG and itsaffiliated companies (SAP Group) for informational purposes only, without representation or warrantyof any kind, and SAP Group shall not be liable for errors or omissions with respect to the materials. Theonly warranties for SAP Group products and services are those that are set forth in the express warrantystatements accompanying such products and services, if any. Nothing herein should be construedas constituting an additional warranty.

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  • About This HandbookThis handbook is intended to complement the instructor-led presentation of thiscourse, and serve as a source of reference. It is not suitable for self-study.

    Typographic ConventionsAmerican English is the standard used in this handbook. The following typographicconventions are also used.

    Type Style Description

    Example text Words or characters that appear on the screen. Theseinclude field names, screen titles, pushbuttons as well asmenu names, paths, and options.

    Also used for cross-references to other documentationboth internal and external.

    Example text Emphasized words or phrases in body text, titles ofgraphics, and tables

    EXAMPLE TEXT Names of elements in the system. These include reportnames, program names, transaction codes, table names,and individual key words of a programming language,when surrounded by body text, for example SELECTand INCLUDE.

    Example text Screen output. This includes file and directory namesand their paths, messages, names of variables andparameters, and passages of the source text of a program.

    Example text Exact user entry. These are words and characters thatyou enter in the system exactly as they appear in thedocumentation.

    Variable user entry. Pointed brackets indicate that youreplace these words and characters with appropriateentries.

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  • About This Handbook TADM10_1

    Icons in Body TextThe following icons are used in this handbook.

    Icon Meaning

    For more information, tips, or background

    Note or further explanation of previous point

    Exception or caution

    Procedures

    Indicates that the item is displayed in the instructor'spresentation.

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  • Contents

    Course Overview .............................................................................. ixCourse Goals.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ixCourse Objectives ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x

    Unit 1: SAP Portfolio Overview..............................................................1

    Unit 2: Navigation ..............................................................................5

    Unit 3: The System Core ......................................................................9

    Logon Groups in AS ABAP... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Fundamental Concepts of Java... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Java Cluster Architecture .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33The Internal Structure of SAP NetWeaver AS Java... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

    Unit 4: Starting and Stopping SAP Systems ........................................... 51

    System Start: Process ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53System Start: AS ABAP and AS ABAP+Java Process... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60Overview of the Process for Starting and Stopping an SAP NetWeaver AS Java . 69Tools for Starting and Stopping SAP Systems... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78Tools for Starting and Stopping ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100System Start: AS ABAP Logs... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .121Java Startup and Control Framework ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .126Logs of the Start and Stop Processes of SAP NetWeaver AS Java ... . . . . . . . . . . . . .136Appendix: Downtime Management .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .142

    Unit 5: Introduction to System Configuration ........................................155

    How the System Evaluates Its Parameters .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .157How to set Profile Parameters .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .166Setting up Operation Modes ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .177Overview of the Administration Tools .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .194Basic Configuration of AS Java with the Config Tool .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .213Configuring AS Java with SAP NetWeaver Administrator.. . . . . . . . . . . . . . . . . . . . . . . . . . .241Further Configuration Activities .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .247

    Unit 6: Software Development in SAP Systems......................................261

    Glossary .......................................................................................265

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  • Contents TADM10_1

    Index ............................................................................................267

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  • Course OverviewCourse TADM10 is the foundation for various, further training courses for consultants.After TADM10, you can continue your training either by taking course TADM12 tofurther expand your knowledge of SAP NetWeaver AS, or by training to become a(Technical) PI or Portal Consultant.

    This training content is largely independent of the type of operating system anddatabase technology.

    Like the other TADM courses, TADM10 comprises several individual courses (orparts thereof), which are arranged here in a way that will enable you to gain theknowledge you require as an SAP Technology Consultant as efficiently as possible.

    Week 1 of course TADM10 is based on content taken from the following courses:

    1. SAPTEC

    2. ADM100

    3. ADM800

    Week 2 of course TADM10 is based on content taken from the following courses:

    1. SAPTEC

    2. ADM100

    3. ADM103

    4. ADM800

    Target Audience

    This course is intended for the following audiences:

    SAP Technology Consultants (Associate Level)

    Course Prerequisites

    Required Knowledge

    Basic knowledge of IT

    Basic knowledge of operating systems and databases

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  • Course Overview TADM10_1

    Course GoalsThis course will prepare you to:

    Work as an Associate Consultant (Junior Consultant) within the SAP technologyenvironment

    Configure and manage SAP NetWeaver AS ABAP

    Configure and manage SAP NetWeaver AS Java

    Course Objectives

    After completing this course, you will be able to:

    Process basic tasks within the technology environment of SAP systems

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  • Unit 1SAP Portfolio Overview

    Unit Overview

    Caution: This unit is distributed as a separate training material.

    Unit ObjectivesAfter completing this unit, you will be able to:

    Unit Contents

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  • Unit Summary TADM10_1

    Unit SummaryYou should now be able to:

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  • Unit 2Navigation

    Unit Overview

    Caution: This unit is distributed as a separate training material.

    Unit ObjectivesAfter completing this unit, you will be able to:

    Unit Contents

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  • Unit Summary TADM10_1

    Unit SummaryYou should now be able to:

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  • Unit 3The System Core

    Unit Overview

    Caution: Some lessons of this unit are distributed as a separate trainingmaterial. The trainer will provide you the correct order of these lessons.

    Unit ObjectivesAfter completing this unit, you will be able to:

    Explain the benefits of logon groups in AS ABAP

    Set up logon groups in AS ABAP

    Use basic Java terminology

    Explain the term Central Services of SAP NetWeaver AS Java

    Understand and use concepts such as Java instance, ICM, and server

    Name the most important managers of the SAP NetWeaver AS

    Name the most important services of the SAP NetWeaver AS

    Unit ContentsLesson: Logon Groups in AS ABAP... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

    Exercise 1: Setting Up Logon Groups ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Lesson: Fundamental Concepts of Java ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Lesson: Java Cluster Architecture.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Lesson: The Internal Structure of SAP NetWeaver AS Java ... . . . . . . . . . . . . . . . 39

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    Lesson: Logon Groups in AS ABAP

    Lesson OverviewThis lesson introduces the concept of logon groups in AS ABAP.

    Lesson ObjectivesAfter completing this lesson, you will be able to:

    Explain the benefits of logon groups in AS ABAP

    Set up logon groups in AS ABAP

    Business ExampleYou want to use logon groups to restrict user logons to certain application servers ofyour system.

    Using Logon GroupsSAP systems sometimes have significantly more than just one or two instances. Eachof these instances offers a specific number of work processes of various types and canaccess the resources of your hardware.

    Situations are conceivable in which the tasks to be performed on an instance placemassive demands on the underlying hardware, thus slowing down all work that iscarried out on this instance. Long dialog response times are particularly annoying,since the end users affected by this incur real costs due to poor system availability.Examples of such situations would be:

    Heavy load due to large numbers of incoming RFC requests

    Heavy load due to complex background work processes

    Heavy load due to numerous update tasks

    Use of dialog groups to separate the dialog load from other loads

    Set up a special logon group to receive RFC requests

    Set up a special logon group for background tasks

    Set up update work processes on just a few selected instances

    Set up a special logon group for dialog tasks

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  • TADM10_1 Lesson: Logon Groups in AS ABAP

    Note that (to use this concept successfully) RFC communication from externalsystems must reference the specially created logon group. It may be worth setting upa logon group named RFC on all your systems, and referencing this logon groupfor every RFC communication to an SAP system. See also SAP Note 593058: NewRFC load balancing procedure.

    Note: For background tasks, special job server groups are created as a logongroup in transaction SM61.

    Using a logon group to ensure the best possible distribution of dialog load

    SAP recommends you set up a single logon group for dialog requests if you want yourend users to have comparable response times.

    This logon group is given the name PUBLIC for example. If you think that it isuseful, you can decide not to include the central instance of your SAP system inthis logon group.

    By default, every instance of an SAP system (including the central instance) isassigned to the logon group SPACE.

    Setting Up Logon GroupsLogon groups are set up in transaction SMLG (Tools CCMS Configuration Logon Groups)).

    Here, you can set up a new logon group and assign the individual instances to this.

    You can display the current status of the instances under Goto Load distribution, aswell as view which instance the next user is assigned to depending on which logongroup is being used.

    When logging on using a logon group, the ABAP message server is always contactedfirst in order to identify the instance with the best performance within the selectedlogon group. The load information is determined by a report on each instance, whichis run automatically every five minutes. This report saves the information in a specialmemory area in the message server, which the SAP GUI can then use to request thebest current instances of a group. To avoid the best current instances of the groupbecoming overloaded with new logons whenever a large number of users attempt tologon within the five minute period, the load information is updated for each instanceafter every fifth logon.

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  • TADM10_1 Lesson: Logon Groups in AS ABAP

    Exercise 1: Setting Up Logon Groups

    Exercise ObjectivesAfter completing this exercise, you will be able to:

    Set up logon groups

    Business ExampleYou want to use logon groups to restrict user logons to certain application servers ofyour SAP System.

    Task: Setting Up Logon GroupsCreate a logon group.

    1. If not already done. Start in your training environments, the SAP Logon program.

    2. Create a logon group called DIALOG- that includes theAdditional Application Server (AAS) instance of your system.

    Hint: The name of the logon group to DIALOG* indicates that dialogrequests should be answered using this logon group.

    3. Create a new entry for your SAP systems. Use the logon group you created inthe previous exercise.

    4. Test the newly created SAP Logon entry and Log on to the System with youruser and password.

    5. Check on which instance you are logged on. (Should be the AdditionalApplication Server (AAS) instance).

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  • Unit 3: The System Core TADM10_1

    Solution 1: Setting Up Logon Groups

    Task: Setting Up Logon GroupsCreate a logon group.

    1. If not already done. Start in your training environments, the SAP Logon program.

    a) The exact path to the SAP Logon program depends on your environment.A SAP Logon program may be available.

    in your classroom

    on the Common Training WTS

    on the operating system of your server twdfSSSS.wdf.sap.corp

    Continued on next page

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  • TADM10_1 Lesson: Logon Groups in AS ABAP

    2. Create a logon group called DIALOG- that includes theAdditional Application Server (AAS) instance of your system.

    Hint: The name of the logon group to DIALOG* indicates that dialogrequests should be answered using this logon group.

    a) Log in to your own ECC system using the SAP Logon entry .User: - Password:

    b) Call the transaction SMLG (or Tools CCMS Configuration LogonGroups).

    c) Either select from the menu: Edit Create assignment or button Createassignment (symbol: white sheet) or the key (F8)

    d) In the resulting window that opens called Create Assignment, enter in fieldLogon Group the following value: DIALOG-.For example: DIALOG-04

    e) In the field instance choose the F4 help and choose the instanceof the Additional Application Server (AAS) named _ _ . The instance number mustmatch to the instance number used in your landscape of the AAS.

    Hint: In practice, this could now be ALL of your AdditionalApplication Server (AAS) instances for this SAP System.

    f) Press the button Copy

    g) Within the overview screen you should now see in front of the instancename of the AAS also your entry called DIALOG- in thecolumn logon group.

    h) Please confirm your entries pressing the Save button (the disk icon)

    i) Leave the transaction SMLG with the symbol: Green arrow back or F3.

    Continued on next page

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    3. Create a new entry for your SAP systems. Use the logon group you created inthe previous exercise.

    a) Within SAP Logon, select Connections

    b) Press New (Symbol white piece of Paper).

    c) Press User Specified System (Default) and select Next

    Hint: Note that in SAP training, SIDs are not unique. This is whyyou have to enter some system details manually.

    d) As Connection Type, choose Group/Server Selection

    e) As Description, enter any text (e.g.( SAP ECC _Logon GroupOwn System)

    f) In the field System ID enter the corresponding 3-digit system ID ofthe system.

    g) In the fieldmessage server enter the hostname of the application server onwhich the message server is running (e.g. twdfSSSS.wdf.sap.corp)

    h) Field SAProuter-String leave blank (unless otherwise specified by theteacher).

    i) In the field Group/Server, enter the Logon group, (for exampleDIALOG-XX) you created in the previous exercise. (If it does not appearcancel your entry with the button Cancel, wait one to two minutes andtry again)

    j) Press the Next button

    k) In the next step called Network settings leave them on the default valuesand press the button Next.

    l) In the next step Select front-end input leave them on the default valuesand press the button Finish

    m) In SAP Logon should now see a new entry, which bears the name of yourchoice in the Description field.

    Hint: You can after you insert the Group/Server field directlychoose the button finish to speed up.

    Continued on next page

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  • TADM10_1 Lesson: Logon Groups in AS ABAP

    4. Test the newly created SAP Logon entry and Log on to the System with youruser and password.

    a) Test the newly created SAP Logon entries in which you double-click it orselect the entry and press the button Log on

    b) If you see a login screen, a dispatcher could be reached with these settings.If this is not the case, and you get an error message, check the SAP logonentry for this system.

    c) Check on the login screen at the bottom right, if the system identifier(SID) appears which you have entered in the previous exercise in the fielddescription.

    d) In the Client field, can be the default value.In the field User enter your user -.In the Password field enter your production password.The field Logon Language you left at the default value.Press the Enter or use the icon on the top left (green check mark)

    5. Check on which instance you are logged on. (Should be the AdditionalApplication Server (AAS) instance).

    a) Select from the top menu in the SAP System Status.

    b) Within the window: System: Status check the Server Name field. Thispanel displays the following information (syntax: ] _ _. The last two digits should match the instance numberof this system, which identifies the instance of Additional ApplicationServer (AAS) (e.g. 01).If this is not the case, verify your SAP Logon entry, or check with thetransaction SMLG if your logon group points to the correct instance.

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  • Unit 3: The System Core TADM10_1

    Lesson Summary

    You should now be able to:

    Explain the benefits of logon groups in AS ABAP

    Set up logon groups in AS ABAP

    Related Information

    SAP Note 51789: Poor user distribution in logon distribution

    SAP Note 64015: Description of test program lgtst

    SAP Note 113440: Default logon group 'SPACE' for load balancing

    SAP Note 118093: Concepts of defining 'limits' in logon load balancing

    SAP Note 888279: Regulating / distributing the workflow load

    SAP Note 986373: RFC load distribution

    SAP Note 593058: New RFC load balancing procedure

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  • TADM10_1 Lesson: Fundamental Concepts of Java

    Lesson: Fundamental Concepts of Java

    Lesson OverviewThis lesson provides a short overview of the fundamental Java concepts for allparticipants that have not yet been confronted with Java. The architectural conceptand the properties of Java are briefly outlined.

    Lesson ObjectivesAfter completing this lesson, you will be able to:

    Use basic Java terminology

    Business ExampleAs of SAP Web Application Server 6.20, you have the option of using Java as well asthe ABAP programming language. You should therefore familiarize yourself with thefundamental concepts of the Java environment.

    IntroductionIf you search for the meaning of the word Java in an encyclopedia, you find thefollowing definitions, among other things:

    One of the four main islands of the Indonesian republic in the Indian Ocean.

    A programming language developed by the company Sun Microsystems.

    An aromatic type of coffee, particularly used to make espresso.

    A popular dance of the 1920s.

    A coarse, loose mesh canvas for embroidery, made of linen or cotton.

    It would undoubtedly be worthwhile to investigate each of these definitionsindividually in more detail. In this course, we want to concentrate exclusively onthe second definition in this list.

    The Java programming language was first introduced in 1995 by Sun MicrosystemsInc.. Java is an object-oriented and platform-independent programming languagethat has spread across many areas. The powerful concept of Java allows thedevelopment of a large number of different types of application - from the classicapplication using applets implemented in Web pages to client/server applications.

    Java has been designed to be platform independent. This means that the same Javaprogram can be executed on any system for which a Java Runtime Environment(JRE) is available. In particular, Java applications can run on different systems that

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  • Unit 3: The System Core TADM10_1

    are based on different hardware. Java can be used to create programs for UNIX,Microsoft Windows, Linux, MacOS, or OS/2, for workstations or servers; for x86,MIPS, Alpha, or Sparc; for computers, organizers, or cell phones, and for the microcomputers built into household and industry devices, such as washing machines,video recorders, cars, and traffic lights.

    Properties of JavaYou need to differentiate between two basic types of Java programs: applicationsand applets.

    Applications

    Java applications are computer programs with the full functional range alsoprovided by other programming languages. Applications can run as localprograms on the user's computer or as client/server systems across the Internetor using an Intranet, or as server programs (servlets, CGI programs) on a Webserver.

    Applets

    The term applet essentially means "little application". It usually means a Javaapplet, a small computer program that runs in a Web browser and is written inthe Java programming language. Java applets are intended for execution withinthe Java Runtime Environment of a browser. They are transferred (as is also thecase, for example, with embedded images) with the HTML page using the HTTPprotocol, and then executed on the client computer. Special security guidelinesapply to Java applets; that is, they are not permitted to perform everything on theclient that locally-installed programs are permitted to. In this way, for example,they can only create network connections to the host from which they weredownloaded.

    Hint: You need to be careful when using the name Java. Not everythingthat has Java as its linguistic root is actually connected to Java; JavaScriptis completely unrelated to Java. JavaScript is a script language that can beembedded in HTML and, with some Web browsers (Netscape, MicrosoftInternet Explorer), produces the execution of certain functions and actionswithin the Web browser. JavaScript was developed with the intention ofdynamically organizing static HTML pages. Unlike server-side scriptlanguages such as Perl or PHP, JavaScript is executed on the client. Incontrast to Java, JavaScript is not an independent programming language,is not independent of the browser version, and does not have the requiredsecurity mechanisms.

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  • TADM10_1 Lesson: Fundamental Concepts of Java

    Initially, Java is a programming language like any other. Unlike traditional compilersfor a programming language, which generate machine code for a specific platform (seethe Compiled Programming Languages figure), the Java compiler produces programcode for a virtual machine (the Java Virtual Machine). This is known as bytecode. Avirtual machine is a model of a processor (which often does not exist as real hardware)and the associated system architecture. It is a computer program that emulates aprocessor. The effort required to transfer this software to other real CPUs is small incomparison. The virtual machine is therefore viewed as the interface between Java andthe actual hardware. It must therefore be developed for each processor architectureand, as such, is the only platform-dependent component of a Java development system(see the figure Concept of the Java Virtual Machine).

    SAP also uses the concept of a cross-platform virtual machine in the ABAP world.The ABAP programs of the SAP system are also converted into a bytecode, which isinterpreted by the ABAP Virtual Machine, the ABAP work process.

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    Figure 1: Compiled Programming Languages

    Hint: Virtual machines play an important role nowadays, since Microsoft hasfollowed Sun's example of the Java Virtual Machine (Java VM) with its .NETarchitecture. The concept of the virtual machine was already in use in the late1960s; Martin Richards' O code for the BCPL programming language is anearly example. Better-known examples are the Pascal P code system (UCSDPascal) from the 1970s, and the virtual machine on which programs in theSmalltalk programming language run.

    The bytecode generated by the Java compiler is comparable to microprocessorcode for a conceived processor , which understands instructions such as arithmeticoperations, gotos, and so on. A Java compiler, such as the one from Sun, which isitself implemented in Java, generates this bytecode. However, so that the programcode of the virtual processor can be executed, after the conversion phase, the runtimeenvironment (also known as the runtime interpreter), the Java Virtual Machine, runsthe bytecode. In this way, Java is a compiled, but also an interpreted programminglanguage.

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  • TADM10_1 Lesson: Fundamental Concepts of Java

    Figure 2: Concept of the Java Virtual Machine

    The interpretation causes speed problems, since the identification, decoding, andexecution of the commands takes time. Java programs are generally slower thanprograms that were converted specifically for the target environment (such as C(++)programs). The technology of the Just In Time (JIT) compiler alleviates the problem.A JIT compiler accelerates the execution of the programs by converting the programstatements of the virtual machine for the physical machine. There is then a programadjusted for the architecture available in memory, which is executed quickly withoutinterpretation. Even with this technology, the speed is slower than that of C in manycases, but the difference is smaller.

    A Java Development Kit (JDK) is required to write platform-independent Javaprograms. The Java Development Kit includes the software required to create and testJava applications and applets, the packages with the Java classes that are part of thebasic configuration, and the online documentation. The software includes the Javacompiler, the Java Runtime Environment (the Java Virtual Machine) for runningapplications, the applet viewer for running applets, a Java debugger, and variousutilities. The online documentation describes all language elements and all classes ofthe Application Program Interface API.

    Java is a relatively new programming language and is therefore still in development,that is, new versions with extensions and improvements are constantly being released:the original version is JDK 1.0 (1995). Since Version 1.2, the JDK has also beencalled Java Platform 2 and in Version 1.3.0 to Version 1.4, the JDK is called Java 2

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  • Unit 3: The System Core TADM10_1

    Software Development Kit (SDK). It is called JDK again from Version 1.5.0 andSDK is used in another context. From Version 1.6.0, Java Platform 2 is no longerused, rather Java Platform is used. From Version 1.5.0, there is a differentiationbetween a developer version and a product version with 1.5.0 as the developer version.The related product version is 5.0. Product version 6 belongs to developer version1.6.0.

    Java Standard Edition (Java SE). The standard edition is the normal softwareenvironment and defines the Java SE Development Kit (JDK). This includesthe Java SE Runtime Environment (JRE).

    Java Enterprise Edition (Java EE). The enterprise edition builds on the JDKand integrates additional packages such as Enterprise JavaBeans (EJB), servlets,JavaServer Pages (JSP), Java Mail API, and Java Transaction Service (JTS).The Java EE SDK (Software Development Kit) includes the Sun Java SystemApplication Server and requires a JDK.

    Java Micro Edition (Java ME). The micro edition is a small runtimeenvironment for small devices such as Personal Digital Assistants (PDAs) ortelephones.

    The following figure SDK Structure describes the interaction between the termsJava EE SDK, JDK and JRE.

    Figure 3: SDK Structure

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  • TADM10_1 Lesson: Fundamental Concepts of Java

    The Java SE Runtime Environment is also referred to as JRE and contains the runtimeenvironment to which the JVM and other libraries with which Java applications can beexecuted belong. The JRE cannot be used to develop any Java programs. The JDK isrequired for this. It contains the JRE with the Java compiler javac and other toolswhich are of use for programming. When performing client-server programming, youneed a server. The SDK contains the reference implementation of an applicationserver, namely the Sun Java System Application Server. You can use the JavaEE SDK to program, among other things, Enterprise Java Beans, Servlets andJSP; however, a JDK is required.

    Figure 4: AS Java with SAP JVM

    SAP NetWeaver AS Java is the SAP implementation for a Java-based applicationserver. SAP NetWeaver AS Java 7.3x is Java EE 6-compliant and was the first(along with Sun) to correspond to this standard. SAP NetWeaver AS Java 7.3x doesnot require a JDK from the operating system manufacturer (unlike its predecessors);instead, the SAP-specific JDK is used on all operating systems.

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    The SAP Java Virtual Machine (JVM) is a Java Virtual Machine for applicationservers that are reliable, scalable and can be supported for using SAP products. TheSAP JVM implements the standard Java SE 5.0 and provides a reliable foundationfor SAP NetWeaver AS Java. Some of the SAP JVM properties were developedespecially to meet the requirements of SAP customers:

    Additional Supportability

    The SAP JVM provides functions for supporting complex Java applications.One prominent function here is the extended stack trace. It helps developers toidentify problems and software errors.

    Profiling and Memory Debugging

    Discovering problems in memory management has the same value as identifyingfunctional errors. Therefore, the SAP JVM provides enhanced options in thearea of performance and memory profiling.

    Debugging on demand

    You can use the SAP JVM in productive use to switch to and back fromdebugging mode without restarting the VM. This dramatically reduces theamount of effort required for troubleshooting.

    For details of available SAP JVM patches, see SAP Note 1434916: How to findout the SAP JVM build version.

    Programming in JavaWhen creating Java programs, the developer first creates a source file in the formatMyProgram.java (see the figure Tools of the Java Development Kit).

    The Java compiler generates a separate file for each class from the source file thatcontains the bytecode for this class. The file name is then the name of the class withthe extension .class, and therefore has the format MyProgram.class. In accordancewith the object-oriented approach, Java functions are grouped in classes. Each Javasource file may only contain one public class. The file name of the source file mustthen be the name of this class (which is case-sensitive) with the extension .java.

    This bytecode is platform-independent: irrespective of the type of system on whichthe Java compiler was called, the bytecode can also be executed on any other computersystem, at least in the case of 100% pure Java, which unfortunately cannot beguaranteed for all products.

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  • TADM10_1 Lesson: Fundamental Concepts of Java

    Figure 5: JDK tools

    You can also combine multiple class files into a compressed archive file. Java archivefiles of this type then have, for example, names in the format MyArchive.jar. AJava archive contains files and possibly also entire directory structures in the samecompressed format used by PKZIP and WinZip. They are administered with theprogram jar (Java Archiver); the call is similar to that of the UNIX program tar (tapearchiver). It is not usually necessary to extract or unpack archive files: The Javacompiler and the Java Virtual Machine can read and load the class files directly fromthe archive files. For this purpose, the file name of the archive file must be specified ina defined format.

    The bytecode of a Java application is executed by calling the Java Virtual MachineJVM (in the Java Runtime Environment JRE) in the format java MyProgram.

    In a similar way to sub program libraries in other programming languages, in Javathere are also small Java programs (classes) with precisely defined conventions forthe interfaces that allow reuse in multiple applications (applications and applets).These programs are known as Java Beans.

    Java EE SpecificationJava became popular with the Internet as a language of the World Wide Web. Lifecan be added to static HTML pages using Applets and Java Script. By extendingWeb servers with the Common Gateway Interface (CGI), these can perform simpledatabase accesses and display the results formatted in the browser. However, thesetechnologies are limited in the case of simultaneous accesses from very large numbersof users who expect reliable information and quick response times.

    Sun provides a solution to these problems in terms of server-side architecture forInternet applications with the Java Platform Enterprise Edition (Java EE). JavaEE is a vendor standard for a complete palette of software components, which are

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  • Unit 3: The System Core TADM10_1

    primarily created in the Java programming language. Sun wishes to ensure thatdevelopments comply with the specification of the Java Enterprise Edition usingcompatibility tests for Java EE.

    The purpose of the specifications is to make available a generally accepted frameworkfor developing distributed, multilayer applications with modular components. Clearlydefined interfaces between the components and layers ensure that software componentsfrom different vendors are interoperable, provided they adhere to the specifications.With the Java EE specification, Sun wishes to ensure that Web applications thatconform to the specification run on all Java EE-compatible servers. The applicationlogic is packed in components (Enterprise Java Beans) in accordance with the JavaEE specifications. They represent modular java program components. A containerprovides the components implicitly with the services of the runtime environment.

    Three-level client/server architectures for enterprise applications can be realized inaccordance with the Java EE specifications. The Java EE application server forms thecore of these architectures (see the figure Three-Level Java(TM) EE Architecture).

    Figure 6: Three-Level Java(TM) EE Architecture

    The Java EE application server processes client requests, executes the applicationlogic, and returns the results to the clients. The application data is accessed fromthe database level. The application logic is implemented in the form of Enterprise

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  • TADM10_1 Lesson: Fundamental Concepts of Java

    Java Beans. These are executed in an EJB Container, which is part of the Java EEApplication Server. The communication between the client and the Java EE is basedon Web standards such as HTTP, HTML, and XML. The Java EE server uses JavaServer Pages (JSP) and Java Servlets to generate HTML pages or XML data. JavaServer Pages and Java servlets are executed in aWeb Container, which is, in turn,part of the Java EE Application Server. Java applets can be included in the HTMLpages that are sent to the Web browser. These applets are executed in the browser.

    Java Server Pages (JSP) are a technology developed by Sun, which essentiallyallow the simple dynamic generation of HTML and XML output for a Web server.This technology enables Java code and specific JSP actions to be embedded in staticcontent. The advantage of this technology is that the logic can be implementedindependent of the design. JSP are converted Java source code using a special JSPcompiler. This source code, which corresponds to a Java servlet, is then converted tobytecode by the Java compiler.

    Figure 7: Architecture of the Java(TM) EE Application Server

    Each application component is executed in a container. These containers provide theapplication components with services in accordance with the Java EE specification.Examples of these services are transaction management, availability, security,scalability, client connection, and database access. This means that the developercan concentrate purely on the application logic and does not need to deal with thesesystem functions.

    The following figure shows an example of the processing of a client request bya Java EE Server.

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  • Unit 3: The System Core TADM10_1

    Figure 8: Processing of a Client Request by the Java EE 6 Server

    To achieve the aims of quick response times and reliable information, the Java EEapplication server must also provide scalability and reliability in addition to thefunctional side. The Java EE Server must handle clustering and load balancing for this.

    Java EE Server in the SAP EnvironmentSAP takes into account the increasing importance of Java for creating businessapplications, together with the larger market of Java developers. SAP began afundamental evaluation of Java as early as 1998 and, since SAP Web ApplicationServer 6.20, provides a complete Java EE-compatible runtime infrastructure. Up toRelease SAP NetWeaver AS Java 7.0, they were AS Java J2EE 1.3-compliant; sinceAS Java 7.1x, they are EE 5-compliant, since AS Java 7.3x they are EE 6-complient.The architecture of an application server in accordance with the Java EE specificationis similar to the ABAP runtime environment used for SAP solutions, since both areplatform-independent, executed in a multi-level architecture, and have a separatepresentation logic and business logic.

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  • TADM10_1 Lesson: Fundamental Concepts of Java

    The use of Java EE in SAP technology has the following advantages for SAPNetWeaver Application Server:

    The open integration architecture SAP NetWeaver integrates perfectly into theopenness of Java EE.

    Java EE is further proof of the strategy of platform-independence pursued bySAP.

    The Java EE Connector architecture allows standardized integration of externalapplications.

    Web Services technologies are supported directly by Java.

    The quickly-growing Java community provides simple access to experienceddevelopers.

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  • Unit 3: The System Core TADM10_1

    Lesson Summary

    You should now be able to:

    Use basic Java terminology

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  • TADM10_1 Lesson: Java Cluster Architecture

    Lesson: Java Cluster Architecture

    Lesson OverviewThis lesson describes the architecture of SAP NetWeaver AS Java. The individualcomponents of SAP NetWeaver AS Java and their functions are introduced. A Javacluster encompasses all Java components of an SAP system.

    Lesson ObjectivesAfter completing this lesson, you will be able to:

    Explain the term Central Services of SAP NetWeaver AS Java

    Understand and use concepts such as Java instance, ICM, and server

    Business ExampleAfter the installation of a SAP NetWeaver Application Server Java, configuration isstill required. You should therefore be familiar with the basic architecture of thecluster of SAP NetWeaver Application Server Java.

    The Java Instance ConceptSAP NetWeaver Application Server Java takes the instance concept of SAP Basis,which combines multiple components that are monitored, started, and stopped togetherinto an administrative unit.

    The following components are part of a Java instance:

    The server processes provide the infrastructure in which the Java EE 6applications run.

    The Internet Communication Manager distributes the client requests to thefree server processes of the instance.

    An instance always runs on one physical server, but there can be multiple instances onone server. Within an SAP system, an instance is defined using the system ID (SID) ofthe SAP system and the instance number. An SAP system consists of a database andone or more instances. These instances can either be purely ABAP or Java instances,or instances with ABAP and Java infrastructure, with the instances of a system alwayshaving the same infrastructure (that is, there is no system that has ABAP instances(without Java) and Java instances (without ABAP).

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    The Central Services form a special Java instance. They provide the basis ofcommunication and synchronization within a Java cluster. Another special instance isthe instance that is installed first. It is often referred to as the Primary ApplicationServer Instance or PAS for short. Further instances for a system are referred to asAdditional Application Server Instances or AAS for short.

    To ensure high-performance when processing Java requests, the SAP system can bescaled using the number of server processes for each instances or using the numberof instances.

    Java Cluster ArchitectureAll Java components of an SAP system are known as a Java cluster. A Java clusterconsists of:

    A Java instance with an ICM and at least one server process.

    The Central Services, which contain a message server and an enqueue server.

    A database for the central storage of data.

    Optionally, additional Java instances

    The following figures illustrate an installation with several SAP NetWeaver AS Javainstances.

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  • TADM10_1 Lesson: Java Cluster Architecture

    Figure 9: Cluster with Multiple SAP NetWeaver AS Java Instances

    ICM and Server ProcessesClient requests to SAP NetWeaver AS Java are received by ICM. It selects a freeserver process to process the request and creates the connection between the clientand the server process. The ICM distributes new incoming requests to the availableserver processes using a round robin algorithm. If a connection to the client exists,the request is forwarded to the server process that is already processing requests forthis client.

    The server process of the SAP NetWeaver Application Server Java runs the Javaapplications. The server processes are implemented as multi-threaded servers and cantherefore process multiple requests in parallel. The system or application threadstake over the processing of the requests.

    Central ServicesThe Central Services run on one host and form a separate Java instance. They consistof the Java message server and the Java enqueue server.

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    The Central Services provide the basis for communication and synchronization for theJava cluster:

    The message service administers a list of the ICM and the server processes ofthe Java cluster. It represents the infrastructure for data exchange (small datasetsonly) between the participating nodes. In the case of load balancing between alarge number of Java instances, it also provides the load balancing informationfor the SAP Web Dispatcher.

    The enqueue service administers logical locks that are set in a serverprocess by the executed application program. It is also used for cluster-widesynchronization.

    The Central Services are essentially required when a Java cluster is installed. Theyare started on a host with a separate system number and the system ID (SID) of theentire system.

    Message Service

    The message service is an individual program used to communicate between theelements of a Java cluster. The message service knows all active Java instances.

    The terms message server and message service are used with the same meaning inthe training material. To be precise, the message server is a program/process thatprovides the message service.

    The message service performs the following tasks in the Java cluster:

    Notification of events that arise in the cluster, for example, if a node of thecluster disappears (due to failure or the instance being shut down), or when aservice is started or stopped.

    Communication between different services

    Forwarding of messages and requests to all participants (broadcast)

    Prepare logon information for the SAP Web Dispatcher

    Guaranteed message transmission

    Exchange of cache information in the cluster

    The same technology is used as with the SAP Message Server for the earlier SAPNetWeaver AS versions without Java.

    Enqueue Service

    The enqueue service runs on the Central Services instance of the Java cluster. Itmanages the lock table in the main memory and receives requests for setting orreleasing locks. It uses the tried and tested SAP lock concept.

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  • TADM10_1 Lesson: Java Cluster Architecture

    The terms enqueue server and enqueue service are used with the same meaning in thetraining material. To be precise, the enqueue server is the program or process thatprovides the enqueue service.

    The enqueue service has the following tasks:

    Internally, it is used for synchronization within the Java cluster

    The applications can lock objects are release locks again. The enqueue serviceprocesses these requests and manages the lock table with the existing locks.

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  • Unit 3: The System Core TADM10_1

    Lesson Summary

    You should now be able to:

    Explain the term Central Services of SAP NetWeaver AS Java

    Understand and use concepts such as Java instance, ICM, and server

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  • TADM10_1 Lesson: The Internal Structure of SAP NetWeaver AS Java

    Lesson: The Internal Structure of SAP NetWeaver AS Java

    Lesson OverviewThis lesson introduces the internal architecture of SAP NetWeaver AS. Thisarchitecture is the foundation for realizing a Java EE 6 application server inaccordance with the Java EE 6 specification.

    Lesson ObjectivesAfter completing this lesson, you will be able to:

    Name the most important managers of the SAP NetWeaver AS

    Name the most important services of the SAP NetWeaver AS

    Business ExampleSAP NetWeaver AS Java consists internally of several managers and services. Tobe able to configure these managers and services, you should first understand theirsignificance and functions.

    IntroductionThe internal structure of SAP NetWeaver AS Java is divided into three logical levels(see the figure Internal Structure of SAP NetWeaver AS Java):

    SAP Java Enterprise Runtime - provides fundamental functions of the runtimeenvironment, such as class loading, cluster communication, management ofconfiguration data, and so on .

    AS Java System Components - contain interfaces, libraries, services andfacades.

    Applications Layer - relates to the applications that are deployed and run inSAP NetWeaver Application Server Java.

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  • Unit 3: The System Core TADM10_1

    Figure 10: Internal Structure of SAP NetWeaver AS Java

    The following general rule applies to the interaction between these three logicalentities in SAP NetWeaver AS Java: higher-level components can use the functions ofthe lower-level layers. On the other hand, the lower levels are not aware of the higherlevels and cannot therefore use their functions.

    This rule is a consequence of the start sequence of the individual modules of thesystem. First, the runtime environment is started, then the services are started, andthen the applications are started.

    Communication between the individual components takes place using definedApplication Programming Interfaces (APIs). The components of the higher levels usethese APIs to use functions of the lower levels. The AS Java System components usethe Framework APIs to talk to the SAP Java Enterprise Runtime. The applications cantalk with the AS Java System components either using APIs defined by the Java EE6 specifications, or using proprietary SAP APIs.

    The functions of these logical levels and their interaction are described in thefollowing.

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  • TADM10_1 Lesson: The Internal Structure of SAP NetWeaver AS Java

    SAP Java Enterprise RuntimeThe SAP Java Enterprise Runtime provides the core functions of the system.These core functions are realized by multiple subsystems of the lowest level.These subsystems are called managers. A selection of these managers with a shortdescription is listed below:

    Log Manager:

    manages the process of logging system events. It configures the logging routinesof the kernel. The Log Manager is the first manager that is started during thestartup of SAP NetWeaver Application Server Java.

    Application Thread Manager:

    manages inbound client requests. Searches for free threads to process inboundrequests. If no threads are free, the requests are buffered in a request queue.

    Thread Manager:

    manages threads in which internal operations of SAP NetWeaver AS Java areexecuted.

    Locking Manager:

    Represents the interface between the server process and the enqueue service.

    Configuration Manager:

    Allows SAP NetWeaver AS Java to store and access data in a relational database.Uses the Open SQL for Java Framework to do this.

    Classloading Manager:

    Central location for the registration and removal of loaders and referencesbetween them.

    Cluster Manager:

    Manages the elements of a cluster (server processes) and is responsible for thecommunication in the cluster. It updates information about the status of theindividual elements of a cluster and the services that are provided by it.

    Important settings:

    element.joinPort: Port with which servers listen for inbound connections.

    ms.host: Host on which the Java message server runs.

    Service Manager

    Represents a container in which all services in the cluster are executed.

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  • Unit 3: The System Core TADM10_1

    AS Java System ComponentsThe AS Java System components form the second level within the three-level structureof SAP NetWeaver AS Java. They provide the complete infrastructure for executingJava EE 6 applications and proprietary SAP applications.

    Four types of AS Java System components can be classified:

    Interfaces:

    Agreements that define how different components of SAP NetWeaver AS Javawork together. They do not provide any runtime functions themselves, but ratherare used by services that provide their implementation.

    Libraries:

    They provide names, classes, and objects within SAP NetWeaver AS Java.These objects are created by the system when it loads the library, or when anobject is first requested.

    Services:

    The services that SAP NetWeaver AS Java provides for processing requests aredefined and configured using the Services. Service components can access andutilize functions of the runtime environment through the Framework API. Theyare the most important of these four types of AS Java System components.

    Facades:

    The facades are special APIs that the Java EE API and SAP API use to accesslibraries, interfaces and services.

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  • TADM10_1 Lesson: The Internal Structure of SAP NetWeaver AS Java

    A selection of the most important services with a short description is listed below:

    Security Provider:

    Administration of users and groups and authorization administration. Controlsaccess to resources or applications deployed in SAP NetWeaver AS Java.

    Monitoring Service:

    Allows access to information about the current system status. Provides generaland statistical information, among other things, about the nodes in the cluster,memory utilization, performance, applications, and user connections.

    Log Configurator service

    Manages the configuration of the logging and tracing mechanism of SAPNetWeaver AS Java.

    Deploy Service:

    Manages the deployment of Java applications.

    EJB Container Service:

    Manages all Enterprise Java Beans (session beans, entity beans, andmessage-driven beans), which are executed in the EJB Container of SAPNetWeaver AS Java.

    HTTP Provider:

    Is responsible for processing HTTP requests.

    Applications LayerThe applications form the third level within the architecture of SAP NetWeaver ASJava. The boundary between the applications and the AS Java System components isdefined by the Java EE APIs and a few proprietary SAP APIs. Applications use theseAPIs to utilize the functions of the AS Java System components.

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    An enterprise application can contain different types of application components:

    Servlet: A program module written in the Java programming language, which isused to respond to requests to a Web server in such a way that the content of thereturned HTMLWeb page is dynamically generated. Servlets are standardized inthe context of the Java EE 6 specification.

    Java Server Pages (JSP): Technology for dynamically generating HTML andXML output of a Web server. This technology enables Java code and specificJSP actions to be embedded in static content. The advantage of this technologyis that the logic can be implemented independent of the design. Java ServerPages are converted to Java source code, which corresponds to a Java servlet,using a special JSP compiler.

    Enterprise Java Beans (EJB): Used for the standardized, simplified developmentof business applications using Java. They are part of the central elements ofthe Java EE 6 specification.

    Java Database Connectivity (JDBC): Uniform interface to databases fromdifferent vendors, defined specifically for relational databases. The tasks ofJDBC include creating and managing database connections, forwarding SQLqueries to the database, and converting the results into a format that is usablefor Java and making them available to the program.

    These components reside in different containers of SAP NetWeaver AS Java (seethe figure Containers of SAP NetWeaver AS Java). The containers provide runtimeservices for the application components.

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  • TADM10_1 Lesson: The Internal Structure of SAP NetWeaver AS Java

    Lesson Summary

    You should now be able to:

    Name the most important managers of the SAP NetWeaver AS

    Name the most important services of the SAP NetWeaver AS

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  • Unit Summary TADM10_1

    Unit SummaryYou should now be able to:

    Explain the benefits of logon groups in AS ABAP

    Set up logon groups in AS ABAP

    Use basic Java terminology

    Explain the term Central Services of SAP NetWeaver AS Java

    Understand and use concepts such as Java instance, ICM, and server

    Name the most important managers of the SAP NetWeaver AS

    Name the most important services of the SAP NetWeaver AS

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  • TADM10_1 Test Your Knowledge

    Test Your Knowledge

    1. Which of the programming languages listed below are implementedplatform-independently?Choose the correct answer(s).

    A Fortran B ABAP C Java D C/C++

    2. Briefly describe the function of the Java Virtual Machine (JVM).

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  • Test Your Knowledge TADM10_1

    Answers

    1. Which of the programming languages listed below are implementedplatform-independently?

    Answer: B, C

    ABAP and Java are programming languages that are implementedplatform-independently.

    2. Briefly describe the function of the Java Virtual Machine (JVM).

    Answer: The JVM executes the platform-independent bytecode generated bythe Java compiler on the relevant hardware.

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  • Unit Summary TADM10_1

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  • Unit Summary TADM10_1

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  • Unit 4Starting and Stopping SAP Systems

    Unit OverviewThe topic of this lesson is the starting and stopping of an SAP system. These are twoof the basic tasks of system administration. You will also learn about the available logand trace options, to be able to react correctly if an error occurs.

    Unit ObjectivesAfter completing this unit, you will be able to:

    Describe the process of the start procedure of an SAP system

    Describe the structure of the file system for SAP instances

    Describe the general start process for an SAP NetWeaver AS ABAP.

    Describe the general start process for an SAP NetWeaver AS ABAP+Java.

    Describe which profiles are evaluated.

    Describe the sequence in which the components of an SAP system and startedand stopped

    Describe the general start process for an SAP NetWeaver AS Java

    Describe the general start process for an SAP NetWeaver AS ABAP + Java

    Operate the tools to start and stop an SAP NetWeaver AS ABAP

    Operate the tools to start and stop SAP NetWeaver AS ABAP + Java

    Operate the tools to start and stop SAP NetWeaver AS Java

    Use the AS ABAP start logs to analyze problems

    Use the term Startup and Control Framework

    Describe the individual steps during the start and stop processes of a Javainstance

    Find the storage locations of trace and log files of the Startup and ControlFramework.

    Name the most important trace and log files of the Startup and ControlFramework and review their content.

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  • Unit 4: Starting and Stopping SAP Systems TADM10_1

    Plan and schedule downtimes in your SAP Systems using the SAP SolutionManager.

    Unit ContentsLesson: System Start: Process ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53Lesson: System Start: AS ABAP and AS ABAP+Java Process... . . . . . . . . . . . . 60Lesson: Overview of the Process for Starting and Stopping an SAPNetWeaver AS Java ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69Lesson: Tools for Starting and Stopping SAP Systems... . . . . . . . . . . . . . . . . . . . . . . 78

    Exercise 2: Starting and Stopping the SAP System ... . . . . . . . . . . . . . . . . . . . . . 93Lesson: Tools for Starting and Stopping ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100

    Exercise 3: Tools for Starting and Stopping... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115Lesson: System Start: AS ABAP Logs ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .121Lesson: Java Startup and Control Framework... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .126

    Exercise 4: Java Startup and Control Framework ... . . . . . . . . . . . . . . . . . . . . . .133Lesson: Logs of the Start and Stop Processes of SAP NetWeaver AS Java 136

    Exercise 5: Logs of the Start and Stop Processes of SAP NetWeaver ASJava ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .139

    Lesson: Appendix: Downtime Management .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .142

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  • TADM10_1 Lesson: System Start: Process

    Lesson: System Start: Process

    Lesson OverviewThis lesson provides a general overview of how to start and stop SAP systems. It willdiscuss the areas of the file system that contain the important data for starting instances.

    Lesson ObjectivesAfter completing this lesson, you will be able to:

    Describe the process of the start procedure of an SAP system

    Describe the structure of the file system for SAP instances

    Business ExampleAs the administrator of SAP systems, you need to stop the systems for maintenancepurposes or after changing system parameters, and then restart them.

    Start Process of the SAP SystemThe starting of an SAP system is the basic prerequisite for being able to work withthe system. Restarts of SAP systems are also required after maintenance work on thehardware in use and changes to the SAP system's profile. Starting an SAP system is aninitial process with which every administrator should be familiar.

    The start process covered in this lesson describes the process for starting an SAPsystem. Every SAP system has a database and at least one instance. An SAP systemwith a Java stack also has a Central Services instance. A system with an ABAP stackcan contain an ABAP Central Services instance that provides the ABAP enqueueservice and the ABAP message server. In this case, the PAS instance does not havean enqueue work process or a message server. An SAP system with an ABAP andJava stack can therefore have two Central Services instances: one for Java, and onefor ABAP.

    The figure Start Process of an SAP System shows the start process of an SAP system.If the SAP system has an ABAP Central Services instance or a (Java) Central Servicesinstance, these are started first.

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  • Unit 4: Starting and Stopping SAP Systems TADM10_1

    Figure 11: Start Process of an SAP System

    Then the PAS instance is started. The PAS instance requires a running database (as dothe ASS instances). If the database has not yet been started, this is started first duringthe start process of the PAS instance. The database can also be started before theactual SAP system is started or with SAP MC via SAP Host Agent.

    The start sequence will be explained in more detail below. The instances of SAPsystems can be divided into three different categories with different priorities for thestart and stop process.

    1. Instances with enqueue but without ABAP dispatcher

    2. Instances with enqueue and with ABAP dispatcher

    3. All other instances

    The enqueue process, which occurs on only one instance for each ABAP/Java stack,plays a special role in the start sequence. These instances, which normally also includethe message server, must be started before all other instances. The (Java) CentralServices instance or an ABAP Central Services instance (priority 1) do not requirea running database, which is why the database is not started when either of theseinstances is started. PAS instances with an ABAP dispatcher and an enqueue workprocess (priority 2) as well as AAS instances (priority 3) require a started database

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  • TADM10_1 Lesson: System Start: Process

    that the ABAP work processes or the Java server processes log on to. Therefore,the first step is to start the database when starting this type of instance (unless it isalready running and installed on the computer on which the PAS- and AAS instanceis installed.). If the SAP system has an ABAP Central Services instance, then thissystem does not contain a Priority 2 instance.

    Fundamentally, the start process is performed in multiple steps. The start process istriggered with the operating system user adm:

    Starting the Central Services instance(s)

    The (Java) Central Services consist of the Java message server and the Javaenqueue server, and the ABAP Central Services provide the ABAP messageserver and the ABAP enqueue server.

    Starting the database

    The underlying element of the entire SAP system is the database. This mustbe in an operational state before starting SAP instances that provide ABAPwork processes or Java server processes. However, it may not run or be startedbefore the Central Services instance is started. When a PAS or AAS instance isstarted, the system checks whether the database is running when the start processis triggered, and starts it if necessary.

    Starting the PAS instance

    In an AS ABAP or ABAP+Java system, the PAS instance has priority 2 if thereis no ABAP Central Services instance and the instance has an enqueue workprocess; otherwise the PAS instance has priority 3 just like the AAS instances. APAS instance with priority 2 is started before the AAS instances, while a PASinstance with priority 3 is started at the same time as the AAS instances. In anAS Java system, the PAS instance always has priority 3, and is always startedwith the AAS instances.

    Starting the AAS instance(s)

    If the PAS instance has priority 3, the AAS instances are started at the same timeas the PAS instance. If the PAS instance has priority 2, the AAS instances arestarted once the PAS instance start process has finished.

    Stop Process

    An SAP system is stopped in the opposite sequence. The instances with enqueueare always stopped last.

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  • Unit 4: Starting and Stopping SAP Systems TADM10_1

    Evaluating the Profiles in the Start ProcessEach instance of an SAP system requires data in the file system. This includes datathat all instances can access (globally), and data that can only be accessed by aninstance individually. In the file system, the data for the instances is contained inthe usr/sap directory, where it is further organized into subdirectories. The figureStructure of the File System of an AS ABAP+Java (simplified) shows this structure.The structure of an AS ABAP system differs the fact that the j2ee directories aremissing in the instance directories and no SCS directory exists.

    Hint: The business data and similar data is contained in the database,which has its own structures in the file system depending on the databasemanufacturer. This data is not contained in the usr/sap directory.

    Figure 12: Structure of the File System of an AS ABAP+Java (simplified)

    The directory contains all data that must only be accessed by this SAPsystem. The data for the PAS instance of an SAP system with an ABAP stack islocated in the DVEBMGS directory (where is the instance number). Thisdirectory includes other directories such as work, which contains the logs of the startprocess for example, the j2ee directory, which contains data about the Java nodesand other information, and the exe directory, which contains the kernel. The kerneldirectory includes the programs that are started when the system is started. The

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  • TADM10_1 Lesson: System Start: Process

    directories of the AAS instances for a SAP system with an ABAP stack have the nameD and have the same structure as the PAS instance. The directory SCS isfor the Central Services instance of an SAP system with a Java stack. Usually, thePAS instance and all AAS instances are located on separate hosts. This means eachAAS instance also has its own directory. If several AAS instances are installed onone host, these have different instance numbers. The SYS directory contains datathat can be accessed by all instances: On Windows operating systems, it is usuallylocated in the file system in which the PAS instance is located. On other operatingsystems, the SYS directory is located in its own file system with the name sapmnt. OnWindows operating systems, share is created on the sap directory above SYS withthe name sapmnt. This Share allows all instances to access the SYS directory. On otheroperating systems, a SYS directory is created in the file system of each instance, whichcontains links to the subdirectories of the sapmnt file system.

    The SYS directory contains the following subdirectories in particular:

    global contains global data

    profile contains the default profile and the start and instance profiles

    exe contains the kernel.

    During the start process of an instance, the kernel of the global exe directory isreplicated to the local exe directory of the respective instance with the sapcpe program.On a Windows operating system, the exe directory also contains the subdirectory, which itself contains the subdirectory.

    is uc for Unicode, and nuc for non-Unicode.

    For an AS ABAP+Java system running on a Windows operating system in whichthe ABAP stack is non-Unicode (the Java stack is always Unicode), this means theexe directory contains the two subdirectories nuc and uc. As of Basis release 7.11,operating systems other than Windows have an identical structure to the Windowsoperating systems listed above.

    For SAP NetWeaver 7.0 systems running on operating systems other than Windows,the kernel is contained in the global exe directory. An AS ABAP+Java system witha non-Unicode ABAP stack is an exception. In this case, the non-Unicode kernel isstill located in the global exe directory. There is also a uc subdirectory, in which theUnicode kernel is located in the subdirectory.

    The sapstartsrv program reads the start profile or instance profile at the beginning.

    Hint: From Release SAP NetWeaver AS 7.1x the entries for the startingprocedure are integrated in the instance profile. Start profiles are e.g. insystems of the type ECC 6.06 available.

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  • Unit 4: Starting and Stopping SAP Systems TADM10_1

    The start profile or instance profile defines which steps must be performed duringthe start process or which processes of the instance are started by sapstartsrv. First,sapcpe (Central Patch Environment) is executed, which replicates, copies or linksdirectories and programs. sapcpe is used to replicate the kernel from the globaldirectories to the local exe directory of the instance.

    For example, the start profile or instance profile defines that the database should bestarted if it is not yet running for the PAS instance and the AAS instances. The IGSwatchdog is also started, and on a system with an ABAP stack, the ABAP dispatcheris started and if necessary, the ABAP message server.

    Normally, the start profile or the entries for the starting procedure in instance profileare not changed. If these entries for the start process are changed in the start profiledespite this, sapstartsrv has to be restarted.

    Figure 13: Start and Profile Evaluation of an Instance

    If an instance is started, the parameters of the default and instance profile areevaluated, and the instance is started with these parameters. Parameters are definedin the default profile for all instances. For each instance, there is a separate instanceprofile that defines the parameterization for the respective instance.

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  • TADM10_1 Lesson: System Start: Process

    Lesson Summary

    You should now be able to:

    Describe the process of the start procedure of an SAP system

    Describe the structure of the file system for SAP instances

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  • Unit 4: Starting and Stopping SAP Systems TADM10_1

    Lesson: System Start: AS ABAP and AS ABAP+JavaProcess

    Lesson OverviewDepending on the installation, the SAP NetWeaver Application Server (AS) may runas an AS ABAP, AS ABAP+Java, or AS Java system. However, the infrastructurefor starting and stopping is basically identical, and is introduced in this lesson usingan AS ABAP+Java system as an example. On an SAP NetWeaver AS running as anABAP+Java system, the Java stack is automatically started and stopped by the ABAPdispatcher using the Startup and Control Framework (which this lesson does notdescribe in more detail). The tools used to run the start/stop process are discussed ina later lesson.

    Lesson ObjectivesAfter completing this lesson, you will be able to:

    Describe the general start process for an SAP NetWeaver AS ABAP.

    Describe the general start process for an SAP NetWeaver AS ABAP+Java.

    Describe which profiles are evaluated.

    Business ExampleAs the administrator of SAP systems, you need to stop the systems for maintenancepurposes or after changing system parameters, and then restart them.

    Starting and Stopping an SAP NetWeaver AS ABAPThe instances are started and stopped using tools such as the SAP ManagementConsole (SAP MC). In an instance of a dual-stack system (ABAP+Java), the Javastack is started by the ABAP dispatcher using the Startup and Control Framework,which then starts the Java dispatcher and the server processes.

    The Java cluster elements are started using the Startup and Control Framework.

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  • TADM10_1 Lesson: System Start: AS ABAP and AS ABAP+Java Process

    Figure 14: Starting an SAP NetWeaver AS ABAP without an ABAP CentralServices Instance

    The tools (explained in more detail in a later lesson) can be used to start or stopindividual instances or also the entire system. To start and stop individual instances,follow the sequence of priority of individual instances. However, the infrastructurealso allows the entire system to be started, stopped, or restarted.

    The tools for starting and stopping communicate with the sapstartsrv process, whichalso provides the functions of a Web service. The sapstartsrv process is a service inWindows operating systems; in other operating systems, it is scheduled as a daemon.There is a separate sapstartsrv process for each instance, which is responsible forstarting and stopping the instance. If a sapstartsrv process now receives the startcommand for the system, it must forward this to the other sapstartsrv processes,which is done through HTTP(S). The sapstartsrv processes write a 1-byte controlfile to the $(DIR_GLOBAL)\sapcontrol directory every minute. The name of thecontrol file indicates the port and host on which the process can be accessed, and thepriority of its instance.

    Using the control files, the sapstartsrv process recognizes which other sapstartsrvprocesses are still active, and starts them according to their priority.

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  • Unit 4: Starting and Stopping SAP Systems TADM10_1

    In the above figure, the PAS instance is started first when the overall SAP systemis started (step 1). This is because it has an enqueue work process and is thereforepriority 2. It also has no (Java) Central Services or ABAP Central Services instance.At this point, a check is performed to see whether the database is running (step 2). Ifit is not running, it is started. For the sake of simplicity, the sapcpe (Central PatchEnvironment) step has been omitted. This is run as the first step in the start process ofevery instance (and, if relevant, before the database is started). The ABAP messageserver and the ABAP dispatcher are now started (step 3). The ABAP dispatcher startsits work processes and the ICM. The AAS instance is then started since it has priority3. The start process is similar to the PAS instance start process, but no ABAP messageserver is started because there is only one per system. In step 4, the system checkswhether the database is running. The database was started when the PAS instance wasstarted. Although this appears unnecessary, the reason becomes clear in the nextexample based on an AS ABAP system with an ABAP Central Services instance. Instep 5, the ABAP dispatcher is started, which starts its work processes and the ICM.

    Hint: The database is only started if it runs on the same host as the instance.In a distributed installation, the database has to be started separately.

    In the start process, a timeout is specified for starting instances with the next highestpriority. This means that all instances with the same priority have to be started withinthe timeout so that instances with the next highest priority can be started. With atimeout of 300 seconds, in our case this means that the AAS instance is not started ifthe start process of the PAS instance lasts longer than five minutes. The AAS instancecan be started subsequently, or the value for the system start timeout can be adjusted.

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  • TADM10_1 Lesson: System Start: AS ABAP and AS ABAP+Java Process

    Figure 15: Starting an SAP NetWeaver AS ABAP with an ABAP Central ServicesInstance

    In the above figure, when the overall SAP system is started (step 1), the ABAP CentralServices instance is started first (step 2) because it has priority 1.

    PAS instance and all AAS instances are then started.

    Note: In a system with an ABAP Central Services instance, the enqueue workprocess and the message server into the ASCS instance have been relocated.This means that besides the ASCS instance


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