Two war files in a single ear file and each war files has a static variable

[Suresh Panneer Selvam]

Two war files in a single ear file and each war files has a same static variable. ear is running in single JVM. what is static variable behavior? Will it create separate install for each war or will there single static instance and will share both war files?

Thanks
Suresh Panneerselvam

[Jeanne Boyarsky]

Suresh,
How do they have the same static varaible? Is it in the same class? If so, it can't be in both wars. It can be in a jar used by both wars.

[Pierre-Hugues Charbonneau]

Hi Suresh,

Jeanne is correct.

In summary:

* Default behaviour for application server *

For 1 EAR file with 2 WAR files within same VM, the class loader tree looks like this:

1. System class loader (JDK and application server libraries)
2. Parent class loader (EAR file)
2.1 Child class loader 1 (WAR file #1)
2.2 Child class loader 2 (WAR file #2)

- Static variable defined within code at system class path is visible for everyone
- Static variable defined within EAR file itself e.g. via jar file is visible by both EAR code and both WAR file #1 & #2
- Static variable defined within WAR file itself is only visible to WAR file scope

** Note that each application server provides tuning to override the default behaviour ex: WAR file can override / preferred any class found within parent class loader **

Regards,

[Suresh Panneer Selvam]

Thanks Jeanne & Charbonneau for detailed explanation.