Commons Lang、NumberUtils.isNumber()

import org.apache.commons.lang.math.NumberUtils;

public class C2008122700 {
    public static void main(String[] args) {
        System.out.println(NumberUtils.isNumber("123"));
        System.out.println(NumberUtils.isNumber("1.23"));
        System.out.println(NumberUtils.isNumber("0x10"));
        System.out.println(NumberUtils.isNumber("0x10"));
        System.out.println(NumberUtils.isNumber("0x10a"));
        System.out.println(NumberUtils.isNumber("010a"));

        System.out.println(NumberUtils.isNumber(""));
        System.out.println(NumberUtils.isNumber(null));
    }
}

で、

true
true
true
true
true
false
false
false