import os

if os.sep == '/':

    def get_pid(process):
        field = process.getClass().getDeclaredField('pid')
        field.setAccessible(True)
        return field.getLong(process)

else:

    import ctypes
    GetProcessId = ctypes.cdll.kernel32.GetProcessId
    GetProcessId.argtypes = (ctypes.c_long,)

    def get_pid(proces):
        field = process.getClass().getDeclaredField('handle')
        field.setAccessible(True)
        handle = field.getLong(process)
        return GetProcessId(handle)


if __name__ == '__main__':
    from java.lang import ProcessBuilder
    from java.io import InputStreamReader, BufferedReader

    def read_pid_from_stdout(process):
        reader = BufferedReader(InputStreamReader(process.getInputStream()))
        return reader.readLine()

    builder = ProcessBuilder(["python", "-c", "import os; print os.getpid()"])
    process = builder.start()

    print 'PID from process :', get_pid(process)
    print 'PID from stdout  :', read_pid_from_stdout(process)