package com.itranswarp.learnjava;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import java.nio.charset.StandardCharsets;public class CopyFile {   public static void main(String[] args) throws IOException {      if (args.length != 2) {         System.err.println("Usage:\n  java CopyFile.java <source> <target>");         System.exit(1);      }      copy(args[0],args[1]);   }   static void copy(String source, String target) throws IOException {      String j = "test\\";      source = j + source;      target = j + target;      StringBuilder sb = new StringBuilder();      try(InputStream input = new FileInputStream(source)){         int n;         while((n=input.read()) != -1){            sb.append((char) n);         }      }      try(OutputStream output = new FileOutputStream(target)){         output.write(sb.toString().getBytes(StandardCharsets.UTF_8));      }   }}