Programming Restrictions

The specification lists the following programming restrictions, which you must follow when implementing the methods of an EJB class:

• The EJB is not allowed to start new threads or attempt to terminate the running thread.

• The EJB specification states that "an EJB is not allowed to use read/write static fields. Using read-only static fields is allowed. Therefore, all static fields must be declared as final." This is not a restriction for Oracle8i.

• The EJB is not allowed to use thread synchronization primitives.

• An EJB is not allowed to use the calls to an underlying transaction manager directly. The only exception are enterprise Beans with the TX_BEAN_MANAGED transaction attribute. These beans can use the javax.jts.UserTransaction interface to demarcate transactions.

• An EJB is not allowed to change its java.security.Identity. Any attempt to do so results in the java.security.SecurityException being thrown.

• EJBs are not allowed to use JDBC commit and rollback methods, nor to issue direct SQL commit or rollback commands using SQLJ or JDBC.

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