code: public static final Renderer<Boolean> instance() { // NOPMD it's thread save!
      if (BooleanRenderer.instanceRenderer == null) {
        synchronized (BooleanRenderer.class) {
          if (BooleanRenderer.instanceRenderer == null) {
            BooleanRenderer.instanceRenderer = new BooleanRenderer();
          }
        }
      }
      return BooleanRenderer.instanceRenderer;
    }
docs: returns the instance.
  
  @return Renderer