code: public static List<InstanceStateChange> stopInstances(final List<String> instanceIDs) {
          // pass any credentials as aws-mock does not authenticate them at all
          AWSCredentials credentials = new BasicAWSCredentials("foo", "bar");
          AmazonEC2Client amazonEC2Client = new AmazonEC2Client(credentials);
  
          // the mock endpoint for ec2 which runs on your computer
          String ec2Endpoint = "http://localhost:8000/aws-mock/ec2-endpoint/";
          amazonEC2Client.setEndpoint(ec2Endpoint);
  
          // send the stop request with args as instance IDs to stop running instances
          StopInstancesRequest request = new StopInstancesRequest();
          request.withInstanceIds(instanceIDs);
          StopInstancesResult result = amazonEC2Client.stopInstances(request);
  
          return result.getStoppingInstances();
      }
docs: Stop specified instances (power-on the instances).
  
  @param instanceIDs
  IDs of the instances to stop
  @return a list of state changes for the instances