I’m not sure I believe your symptoms:
- If the
jre
command isn’t found, then runningjre -cp app.jar
should give the same error - Just adding a JAR file to the classpath shouldn’t give the error you’re seeing
I’d expect you to see this error if you run:
java -jar app.jar
The Main-Class header needs to be in the manifest for the JAR file – this is metadata about things like other required libraries. See the Sun documentation for how to create an appropriate manifest. Basically you need to create a text file which includes a line like this:
Main-Class: MainClass
Then run
jar cfm app.jar manifest.txt *.class