[SOLVED] Is there a way within a bash script to determine the minimum java version required by a jar file containing class files and jar files?

Issue

For a single class - we can work out the version of Java used to compile it:

javap -verbose className

I have a scenario where I need to scale this up to a jar file containing many classes and jar files.

My question is: Is there a way within a bash script to determine the java version required by a jar file containing class files and jar files?

Solution

You can extract the JAR file and check the MANIFEST.MF file, which contains information about the JDK used to build the JAR. The "Created-By" or "Build-Jdk" header in the MANIFEST.MF file stores the JDK version used to create the JAR

replace JarName.jar with your jar

here is the bash script to find the jdk version:

#!/bin/bash
jdk_version=$(unzip -p JarName.jar META-INF/MANIFEST.MF | grep "Created-By\|Build-Jdk")
echo $jdk_version

Answered By - Sanjay Nainwal

Answer Checked By - Mildred Charles (WPSolving Admin)