Best practices for shared classloader use?

[Don Asper]

I am considering using the Tomcat 7 shared classloader to reduce the memory 
footprint of my web apps.  But, I'm afraid that loading my application jar 
files into a single classloader will cause lots of problems.  I'm aware that 
the shared classpath should not specify multiple versions of the same class.  
But I suspect, for example, that classes that have static properties must not 
be shared.  Am I correct in thinking this?  Are there other problems that I 
should anticipate?  Thanks!