Сканер сигнатур / src / Hex_code

import javax.swing.*;
import java.awt.*;
import java.lang.String.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.RandomAccessFile;

public class Hex_code {
static String Hex_code(String bytes) {

StringBuffer sb = new StringBuffer(bytes);
if(sb.length()>8) {
while(sb.length()>8) {
sb.delete(0,1);} }
int decimal = Integer.parseInt(sb.toString(),2);
String hexStr = Integer.toString(decimal,16);
return hexStr;
}

static String Hex_file(File file1,JProgressBar progressBar) throws IOException {
progressBar.setValue(30);
System.out.println("Назва файлу = " + file1.getName());
StringBuilder sb = new StringBuilder();
StringBuffer strBuffer = new StringBuffer();
StringBuffer strBuffer1 = new StringBuffer();
strBuffer.setLength(0);
strBuffer1.setLength(0);
int s=0;
try(FileInputStream fin=new FileInputStream(file1))
{
byte[] buffer = new byte[fin.available()];
fin.read(buffer, 0, buffer.length);
for (int i = 0; i < buffer.length; i++) {
String digit = Hex_code(Integer.toBinaryString((int) buffer[i]));
if (digit.length()==1) { strBuffer.append("0"); strBuffer1.append("0");}
strBuffer.append(digit);
strBuffer1.append(digit);
strBuffer.append(" ");
strBuffer1.append(" ");
s++;
if (s%16==0)strBuffer.append("\n");
}
progressBar.setValue(50);
//System.out.print(strBuffer.toString());
}
catch(IOException ex){

System.out.println(ex.getMessage());
}

try(FileWriter writer = new FileWriter("Hex1.txt", false))
{
writer.write(strBuffer.toString());
writer.flush();
progressBar.setValue(60);
}
catch(IOException ex){

System.out.println(ex.getMessage());
}
FileWriter writer = new FileWriter("Hex.txt", false);
writer.write(strBuffer1.toString());
writer.flush();

return strBuffer.toString();
}
}