FAQ: How does the Java Web ADF request multiple resources?
How does the Java Web ADF request multiple resources?
The Java Web Application Developer Framework (ADF) map controls allow multiple resources such as, ArcGIS Server services, ArcIMS Services, Web Map Server (WMS) services, or ArcWeb Services to be combined or blended in a single map.
Once the map is configured, the map is generated as described in the following steps:
1. The browser sends the request for a map using an AJAX call. This request is handled by a postback handler running in a Java application server, such as Tomcat.
2. The postback handler makes simultaneous requests to all the resources that are part of the map except for ArcGIS Server cache resources. It then combines or blends the resources as a single map image.
3. The browser receives the image from the postback handler, and if there are cached resources, then it requests those in parallel and adds them to the map as well.
See the link in related information to better understand how cached resources are handled.