Java Runtime Environment considerations for DS CLI

The DS CLI login procedure IBMDSCLI$MANAGER:IBMDSCLI$LOGIN.COM defines JAVA$CLASSPATH in the OpenVMS process logical name table and it overrides any existing Java classpath definition. If you want to use other Java-based software in the same process, you must redefine JAVA$CLASSPATH so that it provides the classpath as a JAVA command parameter.

The following information provides an overview of how the installation of the DS CLI affects the Java environment of your OpenVMS system.

Because the DS CLI relies on Java Run Time Environment (JRE) V1.4.2, mandatory JRE files are installed in the directory tree that is referenced by the logical name IBMDSCLI$JRE. This setup is according to HP guidelines. The login procedure IBMDSCLI$MANAGER:IBMDSCLI$LOGIN.COM calls the JRE setup procedure which defines several logical names and DCL symbols for usage by the Fast Virtual Machine.

If your OpenVMS host system uses other software that requires JRE but cannot run with the same JRE version as the DS CLI, users of that software can switch between different Java versions. To use different JRE versions, you must run a command procedure to set up the Java environment definitions for the version that you want to use in the given process (see the OpenVMS Java documentation at:

http://h18012.www1.hp.com/java/documentation/1.4.2/ovms/docs/user_guide.html

The DS CLI application-specific Java classes are bundled in Java Archive (.JAR) files in the directory referenced by logical name IBMDSCLI$LIBRARY. These files must be included in the Java classpath. On OpenVMS, two logical names define the classpath:

CLASSPATH: For UNIX-style names. You can use a string inside single quotation marks that consists of colon-separated path names.
JAVA$CLASSPATH: For OpenVMS specification syntax. You can specify multiple paths with a comma-separated expression (not enclosed in single quotation marks) as OpenVMS logical name search list. JAVA$CLASSPATH overrides CLASSPATH, if JAVA$CLASSPATH is defined.

Because of this override process, you might have to redefine the JAVA$CLASSPATH to provide the class path as a JAVA command parameter. However, this JAVA command parameter is only required if you want to use other Java-based software in the same process.