Java Regex to check if the entire string is numeric

Java Regex 

This regex pattern can be used to find if the given string is a number or not.

Pattern

^[-+]?\d*\.?\d+$
 
^[-+]?
Starts with zero or one '-' or '+'
\\d*
zero or more digits
\\.?
zero or one decimal
\\d+$
must end with at least one digit

Example

package com.logicbig.example;


import java.util.regex.Pattern;

public class NumberRegex {
    private static final Pattern PATTERN = Pattern.compile("^[-+]?\\d*\\.?\\d+$");

    public static void main (String[] args) {
        check("3.43");
        check("3.4.3");
        check(".4");
        check("..4");
        check("4.");
        check("4");
        check("-4");
        check("-+4");
        check("1,222.3");
    }

    public static boolean isNumber (String str) {
        return PATTERN.matcher(str)
                      .matches();
    }

    private static void check (String s) {
        System.out.printf("%s  %s%n", s, isNumber(s));
    }
}

Output:

3.43  true
3.4.3  false
.4  true
..4  false
4.  false
4  true
-4  true
-+4  false
1,222.3  false