Example of coping file

 //this is example of function that takes root to the folder where target file lies, and copy there file
 //Contracts_Postpaid_80.xls to the file Contracts_For_VVL.xls which will be created
    public void copyContractsForVVL(String folder) {

        InputStream inStream = null;
        OutputStream outStream = null;

        try {

            File fileToCopy = new File(folder + "//Contracts_Postpaid_80.xls");
            File copiedFile = new File(folder + "//Contracts_For_VVL.xls");

            inStream = new FileInputStream(fileToCopy);
            outStream = new FileOutputStream(copiedFile);

            byte[] buffer = new byte[1024];

            int length;
            //copy the file content in bytes
            while ((length = inStream.read(buffer)) > 0) {

                outStream.write(buffer, 0, length);

            }

            inStream.close();
            outStream.close();

            System.out.println("File is copied successful!");

        } catch (IOException e) {
            e.printStackTrace();
        }
    }