Display BMP on console - Practice Exercises Java

import java.util.*;
public class Main
{
	public static void main(String[] args)
	{
		BinaryReader inputFile;

		String fileName = "";

		if (args.length != 1)
		{
			System.out.println("Please enter filename...");
			fileName = new Scanner(System.in).nextLine();
		}
		else
		{
			fileName = args[0];
		}


		if (!(new java.io.File(fileName)).isFile())
		{
			System.out.println("the file not exists");
			return;
		}


		try
		{
			inputFile = new BinaryReader(File.Open(fileName, FileMode.Open));

			// Leo cabecera 1: deber ser P5
			char tag1 = (char)inputFile.ReadByte();
			char tag2 = (char)inputFile.ReadByte();
			byte endOfLine = inputFile.ReadByte();
			if ((tag1 != 'P') || (tag2 != '5') || (endOfLine != 10))
			{
				System.out.println("The file is not a PGM");
				inputFile.Close();
				return;
			}

			// Leo cabecera 2: ancho y alto
			byte data = 0;
			String sizeOfImage = "";
			while (data != 10)
			{
				data = inputFile.ReadByte();
				sizeOfImage += (char)data;
			}
			String[] widthAndHeight = sizeOfImage.split("[ ]", -1);
			int width = Integer.parseInt(widthAndHeight[0]);
			int height = Integer.parseInt(widthAndHeight[1]);

			// Leo cabecera 3: deber ser 255
			char maxIntensity1 = (char)inputFile.ReadByte();
			char maxIntensity2 = (char)inputFile.ReadByte();
			char maxIntensity3 = (char)inputFile.ReadByte();
			byte endOfLine1 = inputFile.ReadByte();
			if ((maxIntensity1 != '2') || (maxIntensity2 != '5') || (maxIntensity3 != '5') || (endOfLine1 != 10))
			{
				System.out.println("Must be 256 grey levels");
				inputFile.Close();
				return;
			}
		}
		catch (RuntimeException e)
		{
			System.out.printf("Error: %1$s" + "\r\n", e);
		}
	}
}