Start with source file DigitSum.java.

Write a takes inputs an an integer number $($either positive or negative$),$ prints it out, then finds and prints out the sum of all digits in that number.

INPUT VALIDATION: If user enters a string that cannot be parsed into integer, the input must be rejected with an error message containing word ERROR and the prompt must be repeated.

See sample program runs in the example below.

Requirements:

Do not use arrays in your solution.

Do not convert integer into a string in order to extract digits. Use $\%$ operator instead.

Sample #$1-$ valid input

Enter an integer $=>11111$

You entered number $11111.$ The sum of its digits is $5$

Sample #$2-$ valid input

Enter an integer $=>1234$

You entered number $1234.$ The sum of its digits is $10$

Sample #$3-$ invalid input

Enter an integer $=>$ dqdwqqwd

Input ERROR. Number entered was not an integer.

Enter an integer $=>9\mathrm{.}87$

Input ERROR. Number entered was not an integer.

Enter an integer $=>$ dad

Input ERROR. Number entered was not an integer.

Enter an integer $=>-66$

You entered number $-66.$ The sum of its digits is $12$

Test cases:

import java.io$.$ByteArrayInputStream;

import java.io$.$ByteArrayOutputStream;

import java.io$.$PrintStream;

import java.io$.$PrintWriter;

import java.util.regex.Pattern;

public class TestDigitSum $\{$

public static boolean tests$($PrintWriter outputStream$)$

$\{$

int count $=0$;

int expectedCount $=3$;

outputStream.print$("\backslash$r

$----$Tests for DigitSum$--------------------------------------------------------\backslash$r

$")$;

$//$ Test $1//$

outputStream.print$("\backslash$r

$\_\_\_\_$Test $01\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\backslash$r

$")$;

String sep $=$ System.lineSeparator$()$;

String userInput $=$ String.format$("222222222")$;

String expectedOutput $="(?$si$).*?222222222.*18.*"$;

outputStream.print$("\backslash$r

Input:$\backslash$r

$")$;

outputStream.println$($userInput$)$;

outputStream.print$("\backslash$r

Expected output must fit RegEx:$\backslash$r

$")$;

outputStream.println$("\backslash ""+$expectedOutput$+"\backslash "")$;

PrintStream standard $=$ System.out;

ByteArrayInputStream bais $=$ new ByteArrayInputStream$($userInput$.$getBytes$())$;

System.setIn$($bais$)$;

ByteArrayOutputStream baos $=$ new ByteArrayOutputStream$()$;

PrintStream printStream $=$ new PrintStream$($baos$)$;

System.setOut$($printStream$)$;

DigitSum.main$($null$)$;

String actual $=$ baos.toString$()$;

printStream.close$()$;

outputStream.print$("\backslash$r

Actual Output:$\backslash$r

$")$;

outputStream.println$("\backslash ""+$actual$+"\backslash "")$;

outputStream.println$()$;

if$($Pattern$.$matches$($expectedOutput$,$ actual$))$

$\{$

outputStream.printf$("\%-80$s$\%-10$s$\backslash$r

$",$ "DigitSum TEST $01-$ valid positive integer", "PASSED"$)$;

count$++$;

$\}$

else

$\{$

outputStream.printf$("\%-80$s$\%-10$s$\backslash$r

$",$ "DigitSum TEST $01-$ valid positive integer", "FAILED"$)$;

$\}$

$//$ Test $2//$

outputStream.print$("\backslash$r

$\_\_\_\_\_$Test $02\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\backslash$r

$")$;

userInput $=$ String.format$("-112121")$;

expectedOutput $="(?$si$).*?-112121.*8.*"$;

outputStream.print$("\backslash$r

Input:$\backslash$r

$")$;

outputStream.println$($userInput$)$;

outputStream.print$("\backslash$r

Expected output must fit RegEx:$\backslash$r

$")$;

outputStream.println$("\backslash ""+$expectedOutput$+"\backslash "")$;

bais $=$ new ByteArrayInputStream$($userInput$.$getBytes$())$;

System.setIn$($bais$)$;

baos $=$ new ByteArrayOutputStream$()$;

printStream $=$ new PrintStream$($baos$)$;

System.setOut$($printStream$)$;

DigitSum.main$($null$)$;

actual $=$ baos.toString$()$;

printStream.close$()$;

outputStream.print$("\backslash$r

Actual Output:$\backslash$r

$")$;

outputStream.println$("\backslash ""+$actual$+"\backslash "")$;

outputStream.println$()$;

if$($Pattern$.$matches$($expectedOutput$,$ actual$))$

$\{$

outputStream.printf$("\%-80$s$\%-10$s$\backslash$r

$",$ "DigitSum TEST $02-$ valid negative integer", "PASSED"$)$;

count$++$;

$\}$

else

$\{$

outputStream.printf$("\%-80$s$\%-10$s$\backslash$r

$",$ "DigitSum TEST $02-$ valid negative integer", "FAILED"$)$;

$\}$

$//$ Test $3//$

outputStream.print$("\backslash$r

$\_\_\_\_\_$Test $03\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\backslash$r

$")$;

userInput $=$ String.format$("$abc$\%$s$9\mathrm{.}33\%$s$123",$sep, sep$)$;

expectedOutput $="(?$si$).*?$ERROR.$*$ERROR$.*123.*6.*"$;

outputStream.print$("\backslash$r

Input:$\backslash$r

$")$;

outputStream.println$($userInput$)$;

outputStream.print$("\backslash$r

Expected output must fit RegEx:$\backslash$r

$")$;

outputStream.println$("\backslash ""+$expectedOutput$+"\backslash "")$;

bais $=$ new ByteArrayInputStream$($userInput$.$getBytes$())$;

System.setIn$($bais$)$;

baos $=$ new ByteArrayOutputStream$()$;

printStream $=$ new PrintStream$($baos$)$;

System.setOut$($printStream$)$;

DigitSum.main$($null$)$;

actual $=$ baos.toString$()$;

printStream.close$()$;

outputStream.print$("\backslash$r

Actual Output:$\backslash$r

$")$;

outputStream.println$("\backslash ""+$actual$+"\backslash "")$;

outputStream.println$()$;

if$($Pattern$.$matches$($expectedOutput$,$ actual$))$

$\{$

outputStream.printf$("\%-80$s$\%-10$s$\backslash$r

$",$ "DigitSum TEST $03-$ inv