How do I write a J2EE/EJB Singleton?


walkur
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A day ago my application was one EAR, containing one WAR, one EJB JAR, and a couple of utility JAR files. I had a POJO singleton class in one of those utility files, it worked, and all was well with the world:


EAR
|--- WAR
|--- EJB JAR
|--- Util 1 JAR
|--- Util 2 JAR
|--- etc.

Then I created a second WAR and found out (the hard way) that each WAR has its own ClassLoader, so each WAR sees a different singleton, and things break down from there. This is not so good.


EAR
|--- WAR 1
|--- WAR 2
|--- EJB JAR
|--- Util 1 JAR
|--- Util 2 JAR
|---

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