b'Error could not find or load main class caused by java.lang.classnotfoundation error'

I am trying to read the executable jar file using python. That jar file doesn't have any java files. It contains only class and JSON files.

So what I tried is

from subprocess import Popen,PIPE

jar_location = C:\\users\app\\my_file.jar"
inputs = C:\\users\\app\my_input.json"

my_data = Popen(["java", "-cp",jar_location,"SOMECLASS.class",inputs])
stdout,stderr = my_data.communicate()
print(stdout,stderr)

What my expected output is, it reads the input(inputs) and passes it to the given class method(someclass.class) and it should return some response for me.

But the actual output I am getting is a Class file not found error.

The class file is inside the jar file only

I tried with Popen(["java",""-jar",jar_location,inputs]), I am getting no main manifest attribute found. I can see a manifest file with the basic version.

Can someone help me how to read these class files through python? I have to do the same thing for multiple class files which are inside the jar file

from b'Error could not find or load main class caused by java.lang.classnotfoundation error'