import subprocess
import py4j.java_gateway import JavaGateway

def start_java():
    # Note: I assume that my_library.jar contains the library you want to expose with your CLI program.
    ARGS = ['java', '-cp', '/path/to/my_library.jar:/path/to/my/class_dir:/path/to/py4j-java.jar', 'p1.MyApplication']
    p = subprocess.Popen(ARGS)
    print('Java Started: {0}'.format(p.pid))

def stop_java():
    gateway = JavaGateway()
    gateway.shutdown()
    # Two alternatives:
    # (1) You could call a method on the Java side that calls System.exit(0);
    # (2) You could save the pid from start_java and kill the process, but you need to handle mac, linux, and
    #     windows...