import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;

	FileInputStream inFile = new FileInputStream("matrix.txt");
	System.out.println("File is open to read");
	// узнать, сколько байт готово к считыванию
	int bytesAvailable = inFile.available();
	private byte[] bytesReaded;
	System.out.println("Ready to read: " + bytesAvailable + " byte");
	// считать в массив
	int count = inFile.read(bytesReaded,0,bytesAvailable);
	System.out.println("Read: " + count + " byte");
	for (int i=0;i<count;i++)
	System.out.print(bytesReaded[i]+",");
	System.out.println();
	inFile.close();
	System.out.println("Input stream is closed");