Use of ABAP Stack

Question

Can you please let me know what is ABAP Stack

Answer 1

Fundamentals 
Summary
A comprehensive integration and application platform, SAP NetWeaver™ heralds a new approach to IT development and applications. It brings together the disparate worlds of packaged applications and custom development in a single ecosystem, in which enterprise applications as we know them become the building blocks of a new generation of service-oriented applications.
Custom development with SAP NetWeaver™ is about the very latest in application development practices. Efficiency and flexibility are the watchwords. Application development is based on the model-driven paradigm – as little coding as possible, paired with maximum application robustness and flexibility with regard to front-ends. It is about visual, pattern-based programming that still offers complete control for the power developer.
By SAP AG
23 May 2007
Architectural Background
SAP NetWeaver is based on a dual-stack architecture based on ABAP and Java. While ABAP has been with SAP for years and provides a robust and scalable development and runtime environment for any type of business programming, Java is based on open standards and leverages SAP NetWeaver to the broad community of Java developers. In a service-oriented environment, however, the programming language boundaries disappear, since components written in one language (for example, ABAP) can expose their capabilities as services that are consumed by components written in another language (for example, Java). The interoperability is achieved through Web services standards that have been implemented for both stacks. Likewise, SAP’s user interface strategy is built on top of the Web Dynpro programming model that is supported seamlessly both in the Java and in the ABAP space.
The question of which environment you should use when depends on a couple of criteria that have to be weighed up carefully.
ABAP’s strength lies in its proven application server architecture. The language is based on a strong integration of OPEN SQL and manages large data sets known as internal tables. This allows use of ABAP in transaction-oriented environments with good performance. The development environment (ABAP Workbench) is tightly integrated in the application server. Since ABAP is essentially a server-based development infrastructure, work in large development teams is organized by means of the correction and transport system in a distributed development landscape. ABAP supports a variety of data types that are optimized for business processes. Many important engines of SAP NetWeaver such as the BI OLAP engine or the XI integration engine are implemented in ABAP.
Java focuses more on the user interface side although more and more applications make use of the entire Java stack from user interface through business logic to persistence. Many of the ABAP scalability features have been adapted for the Java stack, such as the proven scalability using a J2EE dispatcher and J2EE server nodes (that correspond to the ABAP dispatcher and work processes). The NetWeaver Development Infrastructure organizes distributed development in teams by means of a central repository and build and transportation services similar in philosophy to ABAP’s change and transport system. However, there are subtle differences that have to be taken into account. Java development is carried out on the client side in the NetWeaver Developer Studio. A local J2EE engine makes it easy for Java developers to work offline and later integrate their work in a central test system. Sources are checked out locally so that you only need to connect from time to time to the development infrastructure. SAP has implemented a lot of SAP NetWeaver components in Java, such as the J2EE server itself, the Portal, and the Developer Studio to name just a few.
ABAP and Java are code-based environments. Although they offer model-driven and highly-graphical tools such as the Web Dynpro View Designer or the Web Dynpro Data Modeler you end up in editor and debugger sessions, since most of the developer’s work has to be done here.
Finally, it is important to note that SAP NetWeaver is in transition from an integration platform to a composition and business process platform.
Composite applications can be developed on top of SAP NetWeaver and are supported by the composite application framework (CAF) and Guided Procedures.
Both technologies accelerate composition on top of SAP NetWeaver, but are integrated in the Developer Studio and leverage existing technologies such as Web Dynpro and Adobe Forms integration.
Regards
Ben