java.io.IOException: Stream closed at runner.testrunner.tearDownClass - trying Parallel Execution using Cucumber and TestNG

Question

This is my testrunner file. It throws exception in the tearDownClass().

public class testrunner extends AbstractTestNGCucumberTests { private TestNGCucumberRunner testNGCucumberRunner;

     WebDriver driver;
     WebDriverManager webDriverManager;

      @BeforeClass(alwaysRun = true) 
      public void setUpClass() {
          if(testNGCucumberRunner == null){
                testNGCucumberRunner = new TestNGCucumberRunner(this.getClass());
            }

    }



    @Test(dataProvider = "scenarios")
    public void feature(PickleEventWrapper pickleEvent, CucumberFeatureWrapper cucumberFeature) throws Throwable  {   
    testNGCucumberRunner.runScenario(pickleEvent.getPickleEvent());
    }

@Override
@DataProvider(parallel=true)
public Object[][] scenarios() {
    return testNGCucumberRunner.provideScenarios();
}

@AfterClass(alwaysRun = true)
public void tearDownClass() {

    testNGCucumberRunner.finish();

}
}

From the console:

FAILURE! - in runner.testrunner
runScenario(runner.testrunner)  Time elapsed: 0.01 sec  <<< FAILURE!
java.lang.NullPointerException

runScenario(runner.testrunner)  Time elapsed: 0.011 sec  <<< FAILURE!
java.lang.NullPointerException

tearDownClass(runner.testrunner)  Time elapsed: 56.248 sec  <<< FAILURE!
java.lang.RuntimeException: java.io.IOException: Stream closed
    at runner.testrunner.tearDownClass(testrunner.java:82)
Caused by: java.io.IOException: Stream closed
    at runner.testrunner.tearDownClass(testrunner.java:82)


Results :

Failed tests: 
runner.testrunner.runScenario(runner.testrunner)
  Run 1: testrunner>AbstractTestNGCucumberTests.runScenario:24 » NullPointer
  Run 2: testrunner>AbstractTestNGCucumberTests.runScenario:24 » NullPointer

  testrunner.tearDownClass:82 » Runtime java.io.IOException: Stream closed