You can define a Web application service to monitor Web transactions. A Web application target consolidates all the components of your Web application and determines the availability, performance and usage of the application.

The availability of the Web application can be defined in terms of availability of the Web transactions that are being monitored. For Web applications, Web transactions represent the service tests. A Web application is available as long as the critical functions such as generating a sales report or an online purchase can be performed. Beacons are used to monitor the Web transactions from different geographical locations. You can designate one or more beacons as the "key beacons" that will be used to run the Web transaction. The Web transaction is considered available if it can be executed successfully by any of the key beacons. A Web application can have multiple "key Web transactions" defined. One or more key Web transactions can be used to monitor the availability of the Web application.

Application monitoring is a very important aspect of a project but unfortunately not much attention is paid to develop the effective
monitoring while the project is not live. Once project is live lack of
proper monitoring costs in terms of downtime when support persons are not
aware if application is having some problems or application not
working at all. Discussion on application monitoring should start early at least from the
time when deployment details are being worked out. Some application may
require some specific scripts or tools or authorizations, an early
discussion on monitoring will make it in a better position to address the
delays in its implementation.

This document gives a basic introduction to the challenges , type of
monitoring and best practices which can be followed to ensure high
availability of the live systems. Following topics are covered in this article

1 Challenges in application monitoring
2. Types of Monitoring for application
3. Best Practices in application monitoring
4. Implementation of application monitoring


Article source:http://download.oracle.com/docs/cd/E11857_01/em.111/e18709/T508706T512066.htm
Article source: http://adminschoice.com/application-monitoring