Sample of Py4J Python script

gistfile1.py

import atexit
import platform
import subprocess
import time
from py4j.java_gateway import JavaGateway


class JavaConnection(object):

    JAR_PATH = "./jar/testentrypoint.jar"
    ENTRY_POINT_CLASS = "TestEntryPoint"

    def __init__(self):
        self._gateway = None
        self._process = None
        cmd = ["java", "-jar", self.JAR_PATH, self.ENTRY_POINT_CLASS]
        if platform.system() == "Windows":
            cmd[0] = "javaw"
        self._process = subprocess.Popen(cmd)
        print "JVM started: " + str(self._process.pid)
        atexit.register(self.kill)
        time.sleep(1)  # waiting for JVM start up
        self._gateway = JavaGateway()

    def getString(self):
        return self._gateway.entry_point.getString()

    def kill(self):
        if self._gateway != None:
            self._gateway.shutdown()
            self._gateway = None
        if self._process != None:
            self._process.kill()
            print "JVM killed: " + str(self._process.pid)
            self._process = None


def main():
    jcon = JavaConnection()
    print jcon.getString()
    jcon.kill()

if __name__ == "__main__":
    main()