Overview of the IMS Java dependent regions
The IMS Java™ dependent regions are two types of IMS dependent regions that provide a Java Virtual Machine (JVM) environment for Java applications: Java message processing (JMP) regions and Java batch processing (JBP) regions.
- JMP and JBP regions
- WebSphere® Application Server for z/OS
- Db2 for z/OS stored procedures
- CICS®
JMP and JBP regions can run applications written in Java, object-oriented COBOL, object-oriented PL/I, or a combination of these languages.
To access IMS message queues from your JMP and JBP applications, use the IMS Java dependent region resource adapter. To access IMS databases from your JMP and JBP applications, you can also use these IMS Universal drivers: the IMS Universal JDBC driver and the IMS Universal DL/I driver.
In addition to IMS databases, you can access Db2 for z/OS databases from your JMP and JBP applications by using the JDBC driver for Db2 for z/OS (JCC driver version 3.57.91).
JMP and JBP regions can load and run with a 31-bit or 64-bit Java virtual machine (JVM). Use the JVM=64 or JVM=31 parameter to switch between the 64-bit and 31-bit addressing mode. If no value is specified on JVM=, the 31-bit addressing mode is used.
Java message processing (JMP) regions
JMP regions are like message processing program (MPP) regions, but JMP
regions allow the scheduling only of Java programs. In
the PSB source associated with the Java program, the
option LANG=JAVA
must be specified. A JMP application is started when there
is a message in the queue for the JMP application and IMS schedules the message to be processed. JMP applications, like MPP applications,
are executed through transaction codes submitted by users at terminals and from other
applications. Each transaction code represents a transaction that the JMP application
processes.
A single application can also be started from multiple transaction codes. JMP applications, like MPP applications, are flexible in how they process transactions and where they send the output. JMP applications send any output messages back to the message queues and process the next message with the same transaction code. The program continues to run until there are no more messages with the same transaction code. JMP applications share the following characteristics:
- They are small.
- They can produce output that is needed immediately.
- They can access IMS or DB2® data in a DB/DC environment and DB2 data in a DCCTL environment.
Java batch processing (JBP) regions
JBP regions run flexible programs that perform batch-type processing
online and can access the IMS message queues for
output, like non-message-driven batch message processing (BMP) applications. JBP
applications are started by submitting a job with JCL or from TSO. JBP applications are like
BMP applications, except that they cannot read input messages from the IMS message queue. For example, there is no IN=
parameter in the startup procedure. Like BMP applications, JBP applications can use symbolic
checkpoint and restart calls to restart the application after an abend. JBP applications can
access IMS or Db2 for z/OS data in a DB/DC or
DBCTL environment and Db2 for z/OS data in a DCCTL environment