If you are already running Java™ programs in a JVM, you need to take
the following actions to continue running these applications:
- TThe Language Environment® run-time library SCEERUN2 is now required
to support the IBM® JVM, in addition to the Language Environment run-time library SCEERUN. In your CICS® startup job, the library SCEERUN2 must
be defined in both the STEPLIB and DFHRPL concatenations.
Both
the libraries, SCEERUN and SCEERUN2, must be APF-authorized.
For more information, see in "Installing CICS support for Language Environment" in the CICS Transaction Server for z/OS® Installation Guide
- The library SDFJAUTH is now required for Java support. SDFJAUTH is the partitioned data set extended (PDSE) version of
SDFHAUTH, and it contains some of the components of the SJ domain. A separate
library is needed because these components are now built using XPLink (Extra
Performance Linkage). As for the SDFHAUTH library, the SDFJAUTH library must
be APF-authorized by adding it to the list of APF-authorized libraries in
an appropriate member in SYS1.PARMLIB, and a STEPLIB DD statement must be
provided for it in your startup job stream. "Authorizing
the hlq.SDFHAUTH library" in the CICS Transaction Server for z/OS Installation Guide describes this procedure
for the SDFHAUTH library, and you can follow the same procedure for the SDFJAUTH
library.
- JVM profiles, which contain the JVM initialization options,
are now kept as HFS files, rather than as members of a partitioned data set
(PDS). The DFHJVM DD card in the CICS startup JCL, which referred to the PDS
for the JVM profiles, is no longer required and should be removed. You can
use several different JVM profiles in the same CICS region, and each is stored as a separate
HFS file. The name of each JVM profile (that is, the name of the HFS file)
must still be eight characters or less, so that it can be used in program
definition. Use the JVMPROFILE attribute of a PROGRAM resource definition
to name the JVM profile which is used to construct the JVM that runs the program.
- Ensure that the JVM profiles you want to use are in the HFS
directory that is specified by the new JVMPROFILEDIR system initialization
parameter, or use UNIX soft links to link to the JVM profiles from that
directory. The default setting for the JVMPROFILEDIR system initialization
parameter is /usr/lpp/cicsts/cicsts31/JVMProfiles. That is, the
supplied setting for JVMPROFILEDIR points to the default directory for the
sample JVM profiles. "Enabling CICS to locate the
JVM profiles and JVM properties files" in Java Applications in CICS tells you how
to ensure that CICS can access the JVM profiles in the JVMPROFILEDIR directory,
and how to change it if required (for example, if you chose a different name
during CICS installation for the directory containing the sample JVM profiles).
Note that the JVM profiles DFHJVMPR and DFHJVMCD, and their associated JVM
properties files, must always be available to CICS. Their uses are described later in this
list. Both these JVM profiles must either be present in the directory that
is specified by JVMPROFILEDIR, or linked to by means of UNIX soft links
from that directory.
- If you have modified the supplied sample JVM profiles DFHJVMPR and DFHJVMPS,
and you want to re-use them, migrate these from PDS members to HFS files,
which you can do using the OCOPY TSO command. Note that for CICS Transaction Server for z/OS Version 3 Release 1 , there are changes
to the options that are available in JVM profiles and JVM properties files. Running Java programs in a JVM using the new JVM functions mentions some of these, and the CICS Transaction Server for z/OS Release Guide has
more information about them. The CICS System Definition Guide has
the full lists of options that you can specify using JVM profiles and JVM
properties files. Before you re-use JVM profiles that you used for CICS TS for z/OS, Version 2.2 or CICS Transaction Server for OS/390, Version 1 Release 3,
you should check whether you need to add any of the new options, or to copy
any of the changes to existing options that have been made in the supplied
sample JVM profiles for CICS Transaction Server for z/OS Version 3 Release 1. (For migration from CICS Transaction Server for OS/390, Version 1 Release 3, note in particular that the CICS_HOME parameter
is renamed WORK_DIR.)
- If you decide not to re-use your existing JVM profiles, you
need to set up new JVM profiles that contain settings which are suitable for
your installation, and the paths to the application classes and resources
that are needed for your applications. Note that the JVM profile DFHJVMPR
is used if a Java program is defined as using a JVM but no JVM profile
is specified, and it is used for sample programs, so this JVM profile always
needs to be configured so that it can be used in your CICS region. "Setting up JVM profiles and JVM properties files"
in Java Applications in CICS tells you how to do this.
- CICS-defined programs now have their own JVM profile, DFHJVMCD,
to make them independent of any changes you make to the default JVM profile
DFHJVMPR. DFHJVMCD is used by the default request processor program DFJIIRP,
which is used by the CICS-supplied CIRP request processor transaction, and
by DFJIIRQ, the CICS-key equivalent of DFJIIRP. DFHJVMCD has an associated
JVM properties file, dfjjvmcd.props. You need to make changes to
DFHJVMCD and dfjjvmcd.props to ensure that the settings in them
are suitable for your installation (including the configuration for your JNDI
nameserver). "Customizing or creating JVM profiles
and JVM properties files" in Java Applications in CICS tells you how to do this.
You also need to add classes to the shareable application class path for the
applications that will use the request processor program. For enterprise beans,
you need to add any classes, such as classes for utilities, that are required
by your enterprise beans but are not included in the
deployed JAR files for the enterprise beans. For CORBA stateless objects,
you need to add the JAR files for the applications and any additional classes
that are required. "Enabling applications to use
a JVM" in Java Applications in CICS tells you how to do this.
- Because JVM profiles are now HFS files, case is important. When
you specify the name of a JVM profile (for example, in a PROGRAM resource
definition), you must enter it using the same combination of upper and lower
case characters that is present in the HFS file name. The CEDA panels accept
mixed case input for the JVMPROFILE field irrespective of your terminal's
UCTRAN setting. However, this does not apply when values for this field are
supplied on the CEDA command line, or when you are using another CICS transaction
such as CEMT or CECI. If you need to enter the name of a JVM profile in mixed
case when you use CEDA from the command line or when you use another CICS transaction,
ensure that the terminal you use is correctly configured, with upper case
translation suppressed.
- You
should not specify your own parameters to be passed as environment variables
to your Java application, as you were able to do in CICS Transaction Server for OS/390, Version 1 Release 3. CICS issues warning messages if it finds unknown initialization options in
a JVM profile. Instead, you should use the JVM properties file, which is a
HFS file referenced by the JVMPROPS option in the JVM profile, to pass information
to your Java application. If you have a user.properties file
for your JVMs, you should also migrate the contents to the JVM properties
file as appropriate, because CICS does not look for a user.properties file
for the reusable JVM. The JVM profile itself should only be used to specify
the options described in the CICS System Definition Guide.
- The
user-replaceable module DFHJVMAT, which was introduced in CICS Transaction Server for OS/390, Version 1 Release 3, can
still be used. However, DFHJVMAT is now only invoked if you specify INVOKE_DFHJVMAT=YES
as an option on the JVM profile that you want to override, and if the JVM
profile specifies either REUSE=NO, or the older option Xresettable=NO (that is, it is a single-use JVM). You cannot use DFHJVMAT with JVMs
that are resettable or with the new continuous JVM. Resettable and continuous
JVMs are more economical than single-use JVMs, so it is generally best to
customize a JVM profile rather than using DFHJVMAT to override it. You can
also use different JVM profiles to specify different sets of options, but
you can only specify a single set of options using DFHJVMAT. Normally, a JVM
profile provides sufficient flexibility to configure a JVM as required. Wherever
possible, you should replace any function in your existing DFHJVMAT module
using options that you can specify in the JVM profile. You should only use
DFHJVMAT if you need to make unusual modifications. The CICS Customization Guide tells you how to use DFHJVMAT.
- The user-replaceable program DFHSJJ8O,
which was used in CICS Transaction Server for z/OS, Version 2 Release 1 and CICS Transaction Server for z/OS, Version 2 Release 2 to construct the Language Environment enclave for the JVM, has been replaced by the user-replaceable program
DFHJVMRO, which performs the same functions. If you had modified the settings
specified in DFHSJJ8O to match more closely with the storage usage of your
JVMs, you should repeat this process with DFHJVMRO, bearing in mind that the
storage usage of your JVMs might have changed. "Tuning Language Environment enclave storage for JVMs" in the CICS Performance Guide tells
you how to carry out this tuning process, and "Using
DFHJVMRO to modify the Language Environment enclave for a JVM"
in the CICS Customization Guide tells you how to modify the settings in DFHJVMRO.
- CICS now uses the z/OS shared library region, which enables
address spaces to share dynamic link library (DLL) files. This feature enables
your CICS regions to share the DLLs that are needed to create JVMs, rather
than each region having to load them individually. The storage that is reserved
for the shared library region is allocated in each CICS region when the first JVM is started
in the region. The amount of storage that is allocated is controlled by the
SHRLIBRGNSIZE parameter in z/OS. The minimum is 16M, and the z/OS default is
64M. You should check the setting for this parameter and, if necessary, tune
it. "Tuning the z/OS shared library region" in the CICS Performance Guide tells
you how to carry out this tuning process.
[[ Contents Previous Page | Next Page Index ]]