code: public Webcam getWebcam(String name, Dimension dimension) {
          if (name == null) {
              return getWebcam(dimension);
          }
  
          Webcam webcam = webcams.get(name);
          openWebcam(webcam, dimension);
          return webcam;
      }
docs: Returns the webcam by name, null if not found.
  @param name webcam name
  @return webcam instance