What code， inserted at line 21， is called prior to a session being migrated to a different JVM assuming the web application containing MyExample is deployed in a container which supports distributed applications？（）
Which makes the local EJB component accessible to the web components in the web application deployment descriptor？（）
When is the Float object. Created in line 3， eligible for garbage collection？（）
Which is the correct web application deployment descriptor element for defining a servlet initialization parameter？（）
