Application Web Server
An application server can be either a software framework that provides a generalized approach to creating an application-server implementation, without regard to what the application functions are, or the server portion of a specific implementation instance. In either case, the server's function is dedicated to the efficient execution of procedures (programs, routines, scripts) for supporting its applied applications.
Most Application Server Frameworks contain a comprehensive service layer model. An application server acts as a set of components accessible to the software developer through an API defined by the platform itself. For Web applications, these components are usually performed in the same running environment as its Web server(s), and their main job is to support the construction of dynamic pages. However, many application servers target much more than just Web page generation: they implement services like clustering, fail-over, and load-balancing, so developers can focus on implementing the business logic.
Introduction to Apache Tomcat 7.0 Server
Apache Tomcat (or simply Tomcat, formerly also Jakarta Tomcat) is an open source web server and servlet container developed by the Apache Software Foundation (ASF). Tomcat implements the Java Servlet and the JavaServer Pages (JSP) specifications from Sun Microsystems, and provides a "pure Java" HTTP web server environment for Java code to run.
Tomcat is an application server from the Apache Software Foundation that executes Java servlets and renders Web pages that include Java Server Page coding. Described as a "reference implementation" of the Java Servlet and the Java Server Page specifications, Tomcat is the result of an open collaboration of developers and is available from the Apache Web site in both binary and source versions. Tomcat can be used as either a standalone product with its own internal Web server or together with other Web servers, including Apache, Netscape Enterprise Server, Microsoft Internet Information Server (IIS), and Microsoft Personal Web Server. Tomcat requires a Java Runtime Enterprise Environment that conforms to JRE 1.1 or later."Apache Tomcat is an open source software implementation of the Java Servlet and Java Server Pages technologies."
Introduction to IBM Web Sphere Server
IBM® Web Sphere® Application Server offers options for a faster, more flexible Java application server runtime environment with enhanced reliability and resiliency. It supports single server environments and medium-sized configurations, as well as dynamic web applications requiring web tier clustering over multiple application server instances.
Web Sphere Application Server helps you:
-Increase developer productivity with open standards and broad programming models, including lightweight options for web deployments.
-Deploy and manage applications and services without the constraint of time, location or device type.
-Includes the Liberty profile, which is a highly composable, dynamic application server profile.
-Enhance security and control using integrated management and administrative tools.