What is the session? Why we need it?
As the HTTP is a stateless protocol, the web server can response to the request from each client, but it cannot remember previous requests from the same client. It is difficult to build the web site such as shopping on-line that requires to distinguish from different clients to retain contextual information. The session concept is involved to solve there issues.
In session management whenever a request comes for any resource, a unique token is generated by the server and transmitted to the client. We can also say that the process of managing the state of a web based client is through the use of session IDs. Session IDs are used to uniquely identify a client browser, while the server side processes are used to associate the session ID with a level of access.
Generally speaking, there are three methods to implement the session concept:
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Why need JDBC Data Source?
In the J2EE development, the application needs to persist business data into a database. In SAP world, the data can be stored in the ABAP database through RFC calls. Another data repository is the Java database through the SAP Java persistence infrastructure.
During the SAP server installation, a default datasource is set up and intended to be used by all the SAP applications. You can create a new datasource aliases for your application in order to use the default datasource. Besides, you can create a new datasource in order to have a application specific configuration.
How to Administrate JDBC Data Source?
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The JVM (Java Virtual Machine) is an abstract computing machine which is used to execute Java instruction set in the class file. Likes a real computing machine, it has an instruction set and manipulates various memory areas at run time. Generally, there two subsystems in the JVM – the class loader engine and the execution engine. This post try to explain the memory structure in the execution engine. As below figure shows there are five memory area in the runtime data area.
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SAP offers its own JVM – SAP JVM. The SAP JVM is a Java Virtual Machine for robust, scalable and highly supportable application servers, which can be used in conjunction with SAP products. It implements the Java SE 5.0 standard, offering a strong and reliable foundation for the whole SAP Java stack. SAP NetWeaver 7.1 and higher version can utilize the advanced features of SAP JVM.
With SAP JVM, SAP doesn’t need to support the different behavior of third party JVM implementation. The SAP JVM now is the basis for all java applications running on the NetWeaver.
The SAP JVM comes with a complete set of tools, libraries and APIs to develop, deploy, run, and monitor Java programs in an application server environment. Below diagram shows the components that comprise SAP JVM.
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The connection management in Web Dynpro is a difficult topic. Many developers are still confused by the JCo connection even after one year development. In this post, I would like the share my understanding on SAP Web Dynpro Java connection management. Please let me know if I miss anything.
If the Adaptive RFC is chosen to retrieve data from backend R/3 or other SAP systems, developer needs to create two JCo Destinations in SAP NetWeaver Web Dynpro Content Administrator.
Generally, there are two ways to logon the remote server. One is SSO Ticket and the other is defined user. Please find below articles on how to configure the JCo Destination.
Web Dynpro Best Practices: How to Configure the JCo Destination Settings
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SAP delivers various types of program corrections with Support Packages as part of the software maintenance. Support Packages automatically correct a whole range of errors by downloading corrections into the SAP System. Two categories of Support Packages are available: ABAP Support Packages and Java Support Packages.
ABAP Support Packages
ABAP Support Packages contain corrections and updates for the ABAP components of the SAP system that were performed up to a certain point in time.Each Support Package is based on the previous one. If you want to import Support Package 10, for example, you must also import all previous Support Packages (1-9) in one Support Package queue. To import ABAP Support Packages, you use the Support Package Manager (Transaction SPAM).
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The database connection for SAP J2EE engine is created during the AS Java installation. The database user SAP<SID>DB, password and db server connection string is stored in the secure storage file, located at usrsap<SID>SYSglobalsecuritydataSecStore.properties in the installation folder.
These DB information as well as the default administrator user can be maintained using Config Tool (Execute <AS_Java_install_dir>configtoolconfigtool.bat). Start the Config Tool and select secure store. The configuration for the secure storage in the file system appears.
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SAP NWDS (NetWeaver Developer Studio) is an eclipsed-based IDE for SAP Java development. You can download the NWDS 7.0 from SAP Service Marketplace.
How to download NWDS 7.0?
Go to SAP Service Marketplace – http://service.sap.com and choose link SAP Support Portal. you need to login the web site with a S-user account.
In the Support Portal, choose tab Software Downloads and sub tab Support Packages and Patch.
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Guided procedure is a workflow technology that allows SAP customers to build their custom process-based solutions to leverage SAP NetWeaver technical platform and combine existing UI and services to fully map business processes.
The disadvantage of guided procedure is there is no fundamental support of delegation functionality. In a realistic business scenario, this is a must-have functionality, because employee might be not able to response to immediately and want to delegate the task to other employees.
SAP GP provides a limited delegation function for the administrator and it is not convenient for the end user to use.
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KM(Knowledge Management) provides a central, role-specific point of entry to unstructured information from various data sources in the portal. It also provides a set of API to allow other applications to use KM functions.
Below are the steps on how to use KM API in web dynpro application.
Step 1. Go to web dynpro project properties and select ‘Java Build Path’.
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