private function startDynamoJar()
 {
     $javaCmd = "java -Djava.library.path={$this->libPath} " . "-jar {$this->jarPath} -sharedDb -inMemory -port {$this->port}";
     $this->process = new BackgroundProcess($javaCmd);
     $this->process->run();
     if (!$this->process->isRunning()) {
         throw new \RuntimeException("Unable to start local dynamodb");
     }
 }
 public function stop()
 {
     if ($this->process && $this->process->isRunning()) {
         $this->process->stop();
     }
 }