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Getting the major Java version in say a bash script isn’t always quite trivial. It seems like there isn’t a built‐in switch in the Java launcher that prints only the major version (as a clean number) to be reused in a shell script. Thus, we’d typically need to parse the output of the regular version command.

java -version 2>&1 | awk -F '"' '/version/ {print $2}' | awk -F. '{print ($1=="1" ? $2 : $1)}'

This command uses the regular version switch to get the well known output:

# java -version
openjdk version "22.0.2" 2024-07-16
OpenJDK Runtime Environment Corretto-22.0.2.9.1 (build 22.0.2+9-FR)
OpenJDK 64-Bit Server VM Corretto-22.0.2.9.1 (build 22.0.2+9-FR, mixed mode, sharing)

• The first awk extracts the quoted version string
• In the second awk we decided if the version starts with a 1. (like in older Java versions such as 8) or the first field for later versions.

This approach makes it easier to integrate the version number into scripts.