Cucumber for Java

I am just working through the Cucumber for Java book and run into a problem. I get the following error on the cli:

Exception in thread "main" java.lang.NullPointerException
    at java.util.Objects.requireNonNull(Unknown Source)
    at java.util.Arrays$ArrayList.<init>(Unknown Source)
    at java.util.Arrays.asList(Unknown Source)
    at cucumber.runtime.io.FileResourceIterator$FileIterator.<init>(FileResourceIterator.java:50)
    at cucumber.runtime.io.FileResourceIterator$FileIterator.next(FileResourceIterator.java:64)
    at cucumber.runtime.io.FlatteningIterator.moveToNext(FlatteningIterator.java:29)
    at cucumber.runtime.io.FlatteningIterator.moveToNext(FlatteningIterator.java:32)
    at cucumber.runtime.io.FlatteningIterator.hasNext(FlatteningIterator.java:57)
    at cucumber.runtime.io.FileResourceIterator.hasNext(FileResourceIterator.java:25)
    at cucumber.runtime.model.CucumberFeature.loadFromFeaturePath(CucumberFeature.java:103)
    at cucumber.runtime.model.CucumberFeature.load(CucumberFeature.java:54)
    at cucumber.runtime.model.CucumberFeature.load(CucumberFeature.java:34)
    at cucumber.runtime.RuntimeOptions.cucumberFeatures(RuntimeOptions.java:239)
    at cucumber.runtime.Runtime.run(Runtime.java:111)
    at cucumber.api.cli.Main.run(Main.java:36)
    at cucumber.api.cli.Main.main(Main.java:18)

My cucumber.bat is as follows;

javac -cp "jars/*" step_definitions/CheckoutSteps.java
java -cp "jars/*;." cucumber.api.cli.Main -p pretty  --snippets camelcase / -g step_definitions features

…and my CheckoutSteps.java is

 package step_definitions;

import cucumber.api.java.en.*;
import cucumber.api.PendingException;

public class CheckoutSteps(){
   @Given("^the price of a /"([^/"]*)/" is (//d+)c$")
  public void thePriceOfAIsC(String arg1, int arg2) throws Throwable {
      // Write code here that turns the phrase above into concrete actions
      throw new PendingException();
  }

  @When("^I checkout (//d+) /"([^/"]*)/"$")
  public void iCheckout(int arg1, String arg2) throws Throwable {
      // Write code here that turns the phrase above into concrete actions
      throw new PendingException();
  }

  @Then("^the total price should be (//d+)c$")
  public void theTotalPriceShouldBeC(int arg1) throws Throwable {
      // Write code here that turns the phrase above into concrete actions
      throw new PendingException();
  }
}

The first line of the cucumber.bat appears to compile OK but I’m confused by the Excecption. Any ideas?