phantomjs не закрывает сокет (CLOSE_WAIT)

# netstat -alptun
...
tcp        1      0 127.0.0.1:56092         127.0.0.1:2402          CLOSE_WAIT  18946/java      
tcp        1      0 127.0.0.1:36449         127.0.0.1:5734          CLOSE_WAIT  18946/java      
...

try
  {
      final URL url = getCrawlerUrl(httpRequest);
      if (useSnapshot)
          {
              html = readSnapshot(url);
          } 
      if (html == null)
          { 
              driver = new PhantomJSDriver(caps);
              driver.get(url.toString());
              Thread.sleep(500);

              WebDriverWait wait = new WebDriverWait(driver, 2);
              wait.until(ExpectedConditions.invisibilityOfElementLocated(By.cssSelector("div[global-spinner]")));
              html = driver.getPageSource();
              if (useSnapshot)
                  {
                      writeSnapshot(url, html);
                  } 
          }   
  }
catch (Exception ex)
  { 
      ex.printStackTrace();
  }
finally
  {
      if (driver != null)
          { 
              driver.close();
              driver.quit();
          }   
  }

$ phantomjs -v
1.9.8

$ java -version
java version "1.7.0_79"
OpenJDK Runtime Environment (IcedTea 2.5.6) (7u79-2.5.6-1~deb8u1)
OpenJDK 64-Bit Server VM (build 24.79-b02, mixed mode)