JAVA 認證心得 -- SCBCD (2)

Enterprise Java Beans (EJB) Overview
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• A session or entity bean can be redeployed multiple times in the EJB container and each redeployed bean will have a distinct home.
• Each enterprise bean defines its own set of environment entries. All instances of an enterprise bean within the same home share the same environment entries.
• Environment entry values of an enterprise bean are not shared with other enterprise beans. Enterprise bean instances are not allowed to modify the bean’s environment at runtime.
• EJBs are not allowed to make use of java.io package.
• An EJB container is required to allow synchronized access to multiple users of an entity bean. The bean developer need not worry about the synchronization herself.