The JVM is started by the CICS® Java™ launcher, which uses a set of options known as a JVM profile. A JVM profile determines the characteristics of a JVM, and applications specify the JVM profile that they want their assigned JVM to have. In the JVM profiles used by CICS, you can specify standard options that are supported in the persistent reusable JVM runtime environment, and also some non-standard options that are subject to change in future releases of the Java language specification. You can set up several JVM profiles that use different options to cater for the needs of different applications.
JVM profiles are text files stored on HFS, and they list the Java launcher options. Each JVM profile references a JVM properties file, which is another text file containing the system properties for the JVM. (System properties are key name and value pairs that contain basic information about the JVM and its environment, such as the operating system in which the application is running.) Among other things, the JVM properties file determines the security properties of the JVM. You can edit JVM profiles and JVM properties files using any standard text editor. CICS supplies sample JVM profiles and JVM properties files to help you get started.
How CICS creates JVMs explains how CICS uses JVM profiles, and gives an overview of the options that you can specify using JVM profiles and their associated JVM properties files.
As well as determining the characteristics of a JVM, the JVM profiles and JVM properties files are used to specify the class paths, that is, the directories that the JVM searches for the application classes and resources that are needed for your applications. When you have set up your JVM profiles and JVM properties files, you will need to add classes to the class paths for each application that uses the JVM profiles and JVM properties files. Enabling applications to use a JVM tells you how to do this.