Thread: Hashmap

dear all

I want to know real time live example of hashmap and where to use in java web application.
pls provide real time example.

Hello.
Suppose a university wants to display student's grade based on student's id. And of course student id is unique.
For this they can develop one web application in java. The student will enter the id in the browser and the request goes to servlet. The servlet may not want to read grade from database everytime. Because db operations are expensive. So what servlet will do is it will read all the student details (id & grade) at the time of startup and cache then into a HashMap object. In this case, key will be id and value will be grade.
So when the request comes from the browser the servlet will get the grade(i.e. value) based on the id(i.e. key) from the HashMap object.
I suggested one real time example where Hashmaps can be used. You can think of similar examples.

Syed.

thanks