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Static Properties in Classes used by Servlets

 
Mike R.
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Assume I have a class X that has a static method that returns a static property of class X. Class X is used by various servlets in two web applications running under different contexts in the same servlet container.
My question is this - Within what scope is the static method guaranteed to return identical references to the static property of X? Is the property guaranteed to be static within a single web application or across all applications running in the servlet container? Is this at all dependent on the implementation of the servlet container or defined in the servlet specification somewhere?
 
Tim Baker
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As far as I know they are all shared within the same JRE. I can't think of any reason why a container would put different contexts in different JREs. I'm not sure what the JSP spec says about this.
 
Frank Carver
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It's not so much the JRE that matters as the classloader context. Servlet containers are free to load different applications using separate classloaders, and often do. This means that static information in one application is often different from that in another application in the same container.
Why not try it in your container and let us know what happens?
 
Ken Robinson
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From this article, which basically says:
Here's a small change with a big impact: In API 2.3, a servlet container (a.k.a. the server) will ensure that classes in a Web application not be allowed to see the server's implementation classes. In other words, the class loaders should be kept separate.

it appears that it would indeed be seperate. Of course, verifying this in your container as suggested by Frank Carver above is always a great idea.
 
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