Is it possible run a spring boot packaged jar with java -cp “jarName.jar” com.hw.Main?

Question

I am instructed to write a java tool that will run with the following command.

java -cp "jarName.jar" com.hw.Main --param=someParam

I have created the project with spring boot and can run the executable jar with

java -jar "jarName.jar" 

But when I try the first command console thwors error

Error: Could not find or load main class com.hw.Main

Answer 1

No you can't because Spring Boot executable JARs have its own class loader so your Main class is not visible for the normal class loader.

Either you call it with

java -jar jarName.jar --param=someParam

or you need to call

java -cp jarName.jar org.springframework.boot.loader.JarLauncher --param=someParam

Becuase org.springframework.boot.loader.JarLauncher is the Spring Boot main class that launches Spring Boot.

But that's the same as java -jar