Follow the instructions to install Java on z/OS and screw up production.

I downloaded an update to Java on z/OS, and noticed that the instructions would cause problems!

Java is in a directory like

/usr/lpp/java/J7.1        
/usr/lpp/java/J7.1_64     
/usr/lpp/java/J8.0        
/usr/lpp/java/J8.0_64     

I have Java V7 and V8 and 31 and 64 versions

The installation instruction say

cd to /usr/lpp/java and unpax the uploaded SDK8_64bit_SR8_FP6.PAX.Z file.

This will unpack the file into

/usr/lpp/java/J8.0_64

Overwriting your production system with the new version, so it goes live without any testing, and for a few minutes you have a mixture of files from different fixpacks!

What I would suggest is

• Unzip the file gzip -l -d ibm-semeru-open-jre_x64_linux_11.0.20_8_openj9-0.40.0.tar.gz this upacks the file into a .tar – and delete the .gz
• FTP it to z/OS in binary
• Create a ZFS for the new Java.
• mkdir  /usr/lpp/java/new
• mount the ZFS in /usr/lpp/java/new
• cd /usr/lpp/java/new
• pax -ppx -rvzf SDK8_64bit_SR8_FP6.PAX.Z

This will create files under

/usr/lpp/java/new/J8.0_64

Test this by setting

export JAVA_HOME="/usr/lpp/java/new/J8.0_64"

and using it.

When you have finished your testing, you can mount the new ZFS on /usr/lpp/java/J8.0_64 .

You may want to do this as part of an IPL, because an unmount of a ZFS will terminate any thing using the file system – such as z/OSMF.

You could set up /usr/lpp/java/old/J8.0_64 and /usr/lpp/java/new/J8.0_64 and use /usr/lpp/java/J8.0_64 as an alias to one or the other.