please help
package com.codegym.task.task18.task1826;
import java.io.*;
/*
Encryption
*/
public class Solution {
public static void main(String[] args) throws Exception{
if(args[0].equals("-e")){
try(FileInputStream fp = new FileInputStream(args[1]) ; FileOutputStream fw = new FileOutputStream(args[2])){
byte[] buffer = new byte[fp.available()];
fp.read(buffer);
String encrption = "encript";
byte[] newbuffer = encrption.getBytes();
byte[] encptdbuffer = new byte[buffer.length+newbuffer.length];
for(int i = 0 ; i<buffer.length ; i++){
encptdbuffer[i] = buffer[i];
}
for(int i = 0,j = buffer.length-1 ; i<newbuffer.length ; i++,j++){
encptdbuffer[j] = newbuffer[i];
}
fw.write(encptdbuffer);
}catch (FileNotFoundException e){
}
}else if(args[0].equals("-d")){
try(FileInputStream fp = new FileInputStream(args[1]) ; FileOutputStream fw = new FileOutputStream(args[1])){
byte[] buffer = new byte[fp.available()];
fp.read(buffer);
String encription = "encript";
byte[] newbuffer = encription.getBytes();
byte[] decrptedbuffer = new byte[buffer.length - newbuffer.length];
for(int i = 0 ; i<decrptedbuffer.length ; i++){
decrptedbuffer[i] = buffer[i];
}
fw.write(decrptedbuffer);
}
}
}
}