Rules for coding JVM profiles and JVM properties files

The name of a JVM profile can be up to 8 characters in length. The name of a JVM properties file can be any length, but for ease of use, choose either the name of the JVM profile that references it, or another short name.

The name of a JVM profile or JVM properties file can include the following characters:

Acceptable characters
A-Z a-z 0-9 @ # . - _ % & Start of change$End of change ? ! : | " = , ; < >

When creating your own JVM profile or JVM properties file, do not give it a name beginning with DFH, because these characters are reserved for use by CICS®.

As JVM profiles and JVM properties files are HFS files, case is important. When you specify the name of a JVM profile or JVM properties file anywhere in CICS, 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.

Options in a JVM profile, or system properties in a JVM properties file, take the form of a keyword and value separated by an = sign. For example:

VERBOSE=NO
ibm.jvm.events.output=event.log

Each JVM option or system property is therefore a name and value element pair.

Only the JVM options listed in Options in JVM profiles are recognized by CICS for use in a JVM profile. However, there is no such restriction for a JVM properties file. CICS passes all the system properties in a JVM properties file to the JVM unchanged. You should bear in mind that only the system properties described in the CICS documentation are supported by CICS, although the JVM can support a much wider range of system properties. System properties for JVMs documents the system properties that are particularly relevant for JVMs in a CICS environment, including some which are defined by CICS. Persistent Reusable Java Virtual Machine User's Guide, SC34-6201, lists command-line options, JVM options and system properties that are used in a persistent reusable JVM in a z/OS® environment, some of which are provided in a different format by options in the JVM profile in CICS. The IBM® Developer Kit and Runtime Environment, Java 2 Technology Edition, Version 1.4.2 Diagnostics Guide, SC34-6358, which is available to download from www.ibm.com/developerworks/java/jdk/diagnosis/ documents other system properties that are used for JVM trace and problem determination. The Java™ class libraries include other system properties, and applications might have their own system properties. There is no central repository of all system properties for the JVM.

Follow these rules when coding JVM profiles and JVM properties files:

Case sensitivity
All parameter keywords and operands specified in a JVM profile or JVM properties file are case-sensitive, and must be specified exactly as shown in Options in JVM profiles and System properties for JVMs.
Class path separator character
Use the : (colon) character to separate the directory paths that you specify on a class path option. The separator character is defined by the path.separator system property in the JVM properties file, and the colon is the default for this system property, but you can change this. The options that you might use to specify class paths are LIBPATH, CLASSPATH, TMPREFIX and TMSUFFIX in the JVM profile, and ibm.jvm.shareable.application.class.path in the JVM properties file.
Continuation
For JVM options or system properties, the value is delimited by the end of the line in the text file. If a system property or JVM option, such as a class path, that you are entering or editing is too long for an editor window, you can break the line to avoid scrolling. To continue on the next line, terminate the current line with the backslash and a blank (\   ) continuation characters. For example, the LIBPATH option in the CICS-supplied sample JVM profiles is coded as follows:
LIBPATH=\                                    
   /usr/lpp/cicsts/cicsts31/lib:\            
   /usr/lpp/cicsts/cicsts31/ctg:\            
   /usr/lpp/java142/J1.4/bin:\             
   /usr/lpp/java142/J1.4/bin/classic                  
Comments
To add comments in a JVM profile or JVM properties file, precede the comment with a # symbol. Comment lines are ignored when the file is read by the JVM launcher. For example, the following lines are comments taken from the sample JVM properties file dfjjvmpr.props:
# Uncomment the following line to specify a classpath              
# for Java classes that are CICS programs or Corba               
# applications, but not EJB jars.                                  
#                                                                  
# ibm.jvm.shareable.application.class.path=user.jar:user.directory 

JVM profiles and JVM properties files can also contain blank lines, which are also ignored. You can use blank lines as a separator between options or groups of options.

Character escape sequences
Within a property element string, you can code the escape sequences shown in Table 28
Table 28. Escape sequences
Escape sequence Character value
\b Backspace
\t Horizontal tab
\n Newline
\r Carriage return
\" Double quote
\' Single quote
\\ Backslash
\xxx The character corresponding to the octal value xxx, where xxx is between 000 and 377
\uxxxx The Unicode character with encoding xxxx, where xxxx is one to four hexadecimal digits (see note below for more information).
Note:
Unicode \u escapes are distinct from the other escape types. The Unicode escape sequences are processed before the other escape sequences described in Table 28. A Unicode escape is simply an alternative way to represent a character that may not be displayable on non-Unicode systems. The character escapes, however, can represent special characters in a way that prevents the usual interpretation of those characters.
Storage sizes
When specifying Java nonstandard options in a JVM profile, specify storage sizes in multiples of 1024 bytes. Use the letter K to indicate kilobytes, the letter M to indicate megabytes, and the letter G to indicate gigabytes. For example, to specify 6291456 bytes as the initial size of the middleware heap, code Xms in one of the following ways:
Xms=6291456
Xms=6144K
Xms=6M

Related tasks

Setting up JVM profiles and JVM properties files
Related concepts

How CICS creates JVMs
Related reference
Options in JVM profiles
System properties for JVMs
The sample JVM profiles and JVM properties files
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