What is log.d . How it works and in java coding what code is similarly to it if i dont want to use it.

import android.util.Log; ublic class Card ! public static final Str public static final double CARD_AREA MIN 10000; public static final Scalar COLOR-YELLOW = new Scalar(255, 255, 0); public static final int RECTANGLE-NOT-FOUND-CANNY = 1; public static final int RECTANGLE COULD NOT ROTATE=2; public static final int RECTANGLE FOUND 3; public static final int RECTANGLE OUT_OF SCENE 4; public static final int IMG_PROCESS_WIDTH- 320; public static final int IMG PROCESS HEIGHT 240; G-"Card" * Given an image, attempts to find a card in it *@return static ArrayList detect(Mat imageGray) List MatOfPoint> edgeContours- new ArrayList0; Mat imgCanny ImageCanny(imageGray); Mat hierarchy- new Mat0; Imgproc.findContours(imgCanny, edgeContours, hierarchy, Imgproc.RETR LIST, Imgproc.CHAIN_APPROX SIMPLE); Log.d(TAG, "Contour size:"); for (MatOfPoint point : edgeContours) Log.d(TAG, "tcontour size " + point.width0 + "x" + point.height)+"-"point.cols) + "x" + point.rows0): return null