Stream Video from Raspberry Pi to Java-Application via TCP

public class Main extends Application {
	
	// GUI elements
	private ImageView imageView;
	private Button btnStart;

	@Override
	public void start(Stage primaryStage) {
		try {
			BorderPane root = new BorderPane();

			Image image = getBlankImage(320, 240);
			imageView = new ImageView(image);
			imageView.setFitHeight(240);
			imageView.setFitWidth(320);
			root.setTop(imageView);

			btnStart = new Button("Start Camera");
			btnStart.setPrefWidth(100);
			btnStart.setPrefHeight(30);
			btnStart.setOnAction(e -> {
				handleButtonPress();
			});
			root.setBottom(btnStart);

			Scene scene = new Scene(root);
			primaryStage.setTitle("Video Monitor");
			primaryStage.setScene(scene);
			primaryStage.show();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}

protected void handleButtonPress() {

	if (!this.cameraActive) {

		try {
			if (clientSocket == null || clientSocket.isClosed()) {
				clientSocket = new Socket("192.168.0.116", 5001);
				outToServer = new OutputStreamWriter(clientSocket.getOutputStream());
				inFromServer = new InputStreamReader(clientSocket.getInputStream());
			}

			// grab a frame every 33 ms (30 frames/sec)
			CameraRunnable frameGrabber = new CameraRunnable();
			this.timer = Executors.newSingleThreadScheduledExecutor();
			this.timer.scheduleAtFixedRate(frameGrabber, 0, 33, TimeUnit.MILLISECONDS);

			// update the button content
			this.btnStart.setText("Stop Camera");
			this.cameraActive = true;
		} catch (IOException e) {
			e.printStackTrace();
		}
	} else {
		// the camera is not active at this point
		this.cameraActive = false;

		// update again the button content
		this.btnStart.setText("Start Camera");

		// stop the timer
		this.stopAcquisition();

		System.out.println("Close Socket...");
		try {
			while (!timer.isShutdown()) {
				clientSocket.shutdownOutput();
				clientSocket.close();
			}

		} catch (IOException e) {
			e.printStackTrace();
		}

	}
}

private class CameraRunnable implements Runnable {

	@Override
	public void run() {
		String message = "getNewFrame";
		try {
			if (cameraActive) {
				long startTime = System.currentTimeMillis();
				outToServer.write(message);
				outToServer.flush();
				char[] sizeAr = new char[16];
				inFromServer.read(sizeAr);
				int size = Integer.valueOf(new String(sizeAr).trim());
				// System.out.println(size);
				char[] data = new char[size];
				int pos = 0;
				do {
					int read = inFromServer.read(data, pos, size - pos);
					// check for end of file or error
					if (read == -1) {
						break;
					} else {
						pos += read;
					}
				} while (pos < size);
				long timeToGrab = System.currentTimeMillis() - startTime;
				System.out.println(timeToGrab);
				String encoded = new String(data);
				byte[] decoded = Base64.getDecoder().decode(encoded);

				BufferedImage image = ImageIO.read(new ByteArrayInputStream(decoded));

				// convert and show the frame
				Image imageToShow = SwingFXUtils.toFXImage(image, null);
				updateImageView(imageView, imageToShow);
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}

private void stopAcquisition()

{
	if (this.timer != null && !this.timer.isShutdown()) {
		try {
			// stop the timer
			this.timer.shutdown();
			this.timer.awaitTermination(33, TimeUnit.MILLISECONDS);
		}

		catch (InterruptedException e) {
			// log any exception
			e.printStackTrace();
		}
	}
}

public final class Utils {
	/**
	 * Convert a Mat object (OpenCV) in the corresponding Image for JavaFX
	 *
	 * @param frame the {@link Mat} representing the current frame
	 * @return the {@link Image} to show
	 */
	public static Image mat2Image(Mat frame) {
		try {
			return SwingFXUtils.toFXImage(matToBufferedImage(frame), null);
		} catch (Exception e) {
			System.err.println("Cannot convert the Mat obejct: " + e);
			return null;
		}
	}

	/**
	 * Generic method for putting element running on a non-JavaFX thread on the
	 * JavaFX thread, to properly update the UI
	 * 
	 * @param property a {@link ObjectProperty}
	 * @param value    the value to set for the given {@link ObjectProperty}
	 */
	public static <T> void onFXThread(final ObjectProperty<T> property, final T value) {
		Platform.runLater(() -> {
			property.set(value);
		});
	}

	/**
	 * Support for the {@link mat2image()} method
	 * 
	 * @param original the {@link Mat} object in BGR or grayscale
	 * @return the corresponding {@link BufferedImage}
	 */
	private static BufferedImage matToBufferedImage(Mat original) {
		// init
		BufferedImage image = null;
		int width = original.width(), height = original.height(), channels = original.channels();
		byte[] sourcePixels = new byte[width * height * channels];
		original.get(0, 0, sourcePixels);

		if (original.channels() > 1) {
			image = new BufferedImage(width, height, BufferedImage.TYPE_3BYTE_BGR);
		} else {
			image = new BufferedImage(width, height, BufferedImage.TYPE_BYTE_GRAY);
		}
		final byte[] targetPixels = ((DataBufferByte) image.getRaster().getDataBuffer()).getData();
		System.arraycopy(sourcePixels, 0, targetPixels, 0, sourcePixels.length);

		return image;
	}
}