使用consumer时java8 lambdas编译错误

Question

 @Override
public Mat onCameraFrame(CameraBridgeViewBase.CvCameraViewFrame inputFrame) {
    mRgba = inputFrame.rgba();
    contours = new ArrayList<MatOfPoint>();
    hierarchy = new Mat();
    Imgproc.GaussianBlur(mRgba,mIntermediateMat,new Size(9,9),2,2);
    Imgproc.Canny(mRgba, mIntermediateMat, 80, 100);
    Imgproc.findContours(mIntermediateMat, contours, hierarchy, Imgproc.RETR_TREE, Imgproc.CHAIN_APPROX_SIMPLE, new Point(0, 0));
/* Mat drawing = Mat.zeros( mIntermediateMat.size(), CvType.CV_8UC3 );
 for( int i = 0; i< contours.size(); i++ )
 {
Scalar color =new Scalar(Math.random()*255, Math.random()*255, Math.random()*255);
 Imgproc.drawContours( drawing, contours, i, color, 2, 8, hierarchy, 0, new Point() );
 }*/
    hierarchy.release();
            // Imgproc.cvtColor(mIntermediateMat, mRgba, Imgproc.COLOR_GRAY2RGBA, 4)
/* Mat drawing = Mat.zeros( mIntermediateMat.size(), CvType.CV_8UC3 );
 for( int i = 0; i< contours.size(); i++ )
 {
Scalar color =new Scalar(Math.random()*255, Math.random()*255, Math.random()*255);
 Imgproc.drawContours( drawing, contours, i, color, 2, 8, hierarchy, 0, new Point() );
 }*/
    for ( int contourIdx=0; contourIdx < contours.size(); contourIdx++ )
    {
        // Minimum size allowed for consideration
        MatOfPoint2f approxCurve = new MatOfPoint2f();
        MatOfPoint2f contour2f = new MatOfPoint2f( contours.get(contourIdx).toArray() );
        //Processing on mMOP2f1 which is in type MatOfPoint2f
        double approxDistance = Imgproc.arcLength(contour2f, true)*0.02;
        Imgproc.approxPolyDP(contour2f, approxCurve, approxDistance, true);

        //Convert back to MatOfPoint
        MatOfPoint points = new MatOfPoint( approxCurve.toArray() );

        // Get bounding rect of contour
        Rect rect = Imgproc.boundingRect(points);

            Core.rectangle(mRgba, new Point(rect.x, rect.y), new Point(rect.x + rect.width, rect.y + rect.height), new Scalar(255, 0, 0, 255), 3);



    }
    return mRgba;
}

java编译错误。

consumerConfig.subscribe(
  regClient -> regClient.onDiscoveryEvent(
        Constants.PROVIDER_ADD_EVENT, 
        ssfurl-> System.out.println(ssfurl))
);

但是当我改为Anonymous class.it worded.why？

感谢。

编译下面的代码，没问题。

Error:(172, 72) java: cannot find symbol
symbol:  method onDiscoveryEvent(java.lang.String,(ssfurl)->[...]furl))
location: java.lang.Object regClient

ConsumerConfig方法

        consumerConfig.subscribe(new Consumer<RegClient>() {
            @Override
            public void accept(RegClient regClient) {
                regClient.onDiscoveryEvent(Constants.PROVIDER_ADD_EVENT, ssfurl -> System.out.println(ssfurl));
            }
        });

RegClient的方法。

public void onDiscoveryEvent（String eventKey，DiscoveryEvent event）

DiscoverEvent界面

 public List<Provider> subscribe(Consumer<RegClient> callback){
    List<RegistryConfig> registryConfigs = getRegistries();
    if (registryConfigs == null || registryConfigs.isEmpty()){
        throw new InitException("reg center address is empty");
    }
    List<Provider> providers = new ArrayList<>();
    for (RegistryConfig config:registryConfigs){
        RegClient regClient = RegClientFactory.getRegClient(config.getRegisterAddresses());
        List<SSFURL> ssfurls = regClient.subscribe(buildSubscribeURL()).getProviderList();
        callback.accept(regClient);
        if (ssfurls != null && !ssfurls.isEmpty()){
            providers.addAll(getSubscribeProviders(ssfurls));
        }
    }
    return providers;
}