Java: Check for positive integer using regular expression

"^[1-9]\\d*$" is used to match the positive integer.

App.java

package com.sample.app;

import java.io.IOException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class App {

 private static final String regEx = "^[1-9]\\d*$";

 public static boolean isPositiveNumber(int number) {
  Pattern pattern = Pattern.compile(regEx);
  Matcher matcher = pattern.matcher(number + "");
  return matcher.matches();

 }

 public static void main(String args[]) throws IOException {

  System.out.println("Is 123 positive number : " + isPositiveNumber(123));
  System.out.println("Is -123 positive number : " + isPositiveNumber(-123));
  System.out.println("Is 0 positive number : " + isPositiveNumber(0));
  System.out.println("Is 54 positive number : " + isPositiveNumber(54));
  
  
 }
}

Output

Is 123 positive number : true

Is -123 positive number : false

Is 0 positive number : false

Is 54 positive number : true

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