Interaction between two web applications

Question

Hi All,
I have an issue regarding 2 web projects.
I have
web application-----------related context path
project1 ----------path1
project2 ------------path2
Scenario:
Step1)
I have logged in project1 with the foll url:
http://localhost:8080/path1/index.jsp
Step2);
In index.jsp i have a button to navigate to
http://localhost:8080/path2/page1.jsp
Issue:
Here is the issue.I have set one session attribute set in step1 and i need to acces it in step2.Im getting the attribute as null in step2.
Can any one please let me know wht and where the issue is and the solution for it.
Please help me out.
Thanks in advance
cheers,
Shorath

Answer 1

The fundamental problem is that web apps basically have no knowledge of each other. So if you're deploying to seperate WAR files, they're pretty much independent of each other and, specifically, can not share session data at all.
If you want to share data between webapps, you need to use something outside the container (like a database), or you can play games with class loaders, and static class elements, making sure that your common classes are loaded outside of the webapps themselves.
For example, in Tomcat, the shared and common directories hold classes that are loaded by the container directly and presented to your webapps.
If you have a class with static members loaded from the common or shared directory, then both webapps will see the same instances of that class, and can share information that way. However, these classes will not be reloaded if you reload the webapps, only if you restart the container.
The other problem, of course, is that these classes are agnostic of the session, so you'll need to implement your own session management if the data is unique to the users of your application. Kind of a catch-22.