This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
Generally different .wars are loaded by separate classloaders. Hence there will be multiple (and incompatible) copies of any common classes present in those wars. For eg, a singleton won't really be a singleton, and each war will load it's own copy of the class. If you truly want, say a singleton, it should be present up the classloader hierarchy. This can be achieved by placing it in the classpath. This is generally how containers load classes, although there's no guarantee.