Enter Number in text file and sum all number from file in java

import java.util.*;
import java.io.*;



public class FileWriter {


/*
* ########################################################################
*
* Read Numbers and Count Sum from each line;
*
*
* ########################################################################
*/
public static  void readFile()
{
File  file=new File("hello.txt");
 try
 {
int sum=0;
Scanner output=new Scanner(file);
while(output.hasNextLine())
{

String Save=output.nextLine();
System.out.println(Save);
  for(int i=0;i<Save.length();i++)
  {
 char n=Save.charAt(i);
 int b = Character.getNumericValue(n);
  sum=sum+b;
 
  }
System.out.println("Sum= : "+sum);
}

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

 }

}
public static void main(String[] args)
{
try{

String number;
int line;
char check;
Scanner input=new Scanner(System.in);

PrintWriter out=new PrintWriter("hello.txt");
System.out.println("How many Lines you want to write : ");
     line=input.nextInt();
     System.out.println("Enter lines");
   
for(int i=0;i<=line;i++)
{

number=input.nextLine();

/*########################################################################
*
*    check data charchter or interger
*    id data integer then save in file
*    else note save
*  
*#########################################################################    
*/


for(int j=0;j<number.length();j++)
{
                     
  check=number.charAt(j);
  if(check>='0'&&check<='9')
  {
  out.println(number);
  System.out.println("save data  successfully");
  break;
  }
  else
 
  {

  System.out.println("charachters not allowd");  
  break;

  }

}


}

out.close();
}

catch(Exception e)
{

e.printStackTrace();
}
/*
* #####################################################################
*
*                         File Read Function call
*                        
* ######################################################################
*/

readFile();
}

}
output: