Buidling a scalable web apps means,
1. You must ensure that threads associated with client requests are never sitting idle waiting for a blocking operation to complete.
To achieve that, there is a need for Asynchronous processing which provides a mechanism to execute application-specific blocking operations in a new thread, returning the thread associated with the request immediately to the container.
Non blocking I/O in java EE makes it easy for servlets and filter for synchronous mode processing…
Example : Suppose we have a page with mutilple file attchements of the same size limit.
For field a , the user is uploading a file size of 100MB, in fieldb the user is uploading 10MB, and so on
Writing and Reading the file sizes depends on for Non Blockimg I/O
1. Arrival time
2. file size