Could not find or load main class while running a jar?

Question

I am having a multi-module project structure, when I am building a jar from a module, its getting build but when I try to run that jar using:

java -jar <path to  that jar>.jar

It gives this eror:

Could not find or load main class <packageName.ClassNameWhereMyMainMethodIS>.java

How can I resolve this?

Answer 1

You need to create a runnable jar or use

java -cp <path to  that jar>.jar full.package.name.ClassName 

when you don't define a manifest which indicate which class within the JAR file is your application's entry point.

Answer 2

You can run using:

java -cp TestApp.jar com.test.HelloWorld

-cp adds that jar to your classpath