logback-android/src/main/java/ch/qos/logback/core/joran/action/IncludeAction.java
private InputStream openURL(URL url) {
    try {
      return url.openStream();
    } catch (IOException e) {
      optionalWarning("Failed to open [" + url.toString() + "]", e);
      return null;
    }
  }
private InputStream openURL(URL url) {
    try {
      return url.openStream();
    } catch (IOException e) {
      optionalWarning("Failed to open [" + url.toString() + "]", e);
      return null;
    }
  }
Opens the given URL, logging any exceptions
@param url URL of file/resource to open
@return an input stream to the URL; or {@code null} if the URL could not be opened