4.5 Two-Tier Duration for Java Session State

Java session state is split into two tiers. One tier has a longer duration and it encompasses the duration of the other tier. The duration of the shorter tier is the same as before, that is, it starts when a Java method is invoked and ends when JVM exits. The duration of the longer tier starts when a Java method is invoked in the RDBMS session for the first time. This session lasts until the RDBMS session ends or the session is explicitly terminated by a call to the function dbms_java.endsession_and_related_state. This is addressed by the addition of the following two PL/SQL functions to the DBMS_JAVA package, which account for the two kinds of Java session duration:

• FUNCTION endsession RETURN VARCHAR2;

  This function clears any Java session state remaining from previous execution of Java in the current RDBMS session. The return value is a message indicating the action taken.

• FUNCTION endsession_and_related_state RETURN VARCHAR2;

  This function clears any Java session state remaining from previous execution of Java in the current RDBMS session and all supporting data related to running Java, such as property settings and output specifications. The return value is a message indicating the action taken.

Most of the values associated with running Java remain in the shorter tier. The values that can be useful for multiple invocations of JVM have been moved to the longer tier. For example, the system property values established by dbms_java.set_property and the output redirection specifications.