diff --git a/src/python/sikuli.py b/src/python/sikuli.py
index <HASH>..<HASH> 100644
--- a/src/python/sikuli.py
+++ b/src/python/sikuli.py
@@ -90,7 +90,7 @@ class SikuliLibrary(object):
         if len(jarList) != 1:
             raise Exception('Sikuli jar package should be exist in lib folder')
         sikuliJar = jarList[0]
-        command = 'java -jar '+sikuliJar+' %s ' % str(self.port)+self._get_output_folder()
+        command = 'java -jar '+sikuliJar+' %s %s' % (str(self.port), self._get_output_folder())
         process = Process()
         process.start_process(command, shell=True, stdout=self._output_file(), stderr=self._err_file())
         self.logger.info('Start sikuli java process on port %s' % str(self.port))
fix command format for launching java process