Testing for an integer in java

I was just wondering if there was a simple and easy way to test if a string(single char string) is a number.

Maybe some method I do not know about, or maybe something like

if (string[1].equals(\\#))

Any thoughts?

public class IsStringAnInteger {

    private static IsStringAnInteger instance;

    public IsStringAnInteger getInstance() {
        if (instance == null) {
            instance = new IsStringAnInteger();
        }
        return instance;
    }[code]public class IsStringANumber {

    private static IsStringANumber instance;

    public IsStringANumber getInstance() {
        if (in

    public bool isStringAnInteger(String isThisStringAnInteger) {
        boolean stringIsAnInteger = false;
        int min = getMinimumInteger();
        int max = getMaximumInteger();
        for (int val = min; val <= max; val++) {
            Integer integer = new Integer(val);
            String stringWhichIsAnInteger = integer.toString();
            if (isThisStringAnInteger.equals(stringWhichIsAnInteger)) {
                stringIsAnInteger = true;
            }
        }
        return stringIsAnInteger;
    }

    private int getMinimumInteger() {
        return Integer.MIN_VALUE;
    }

    private int getMaximumInteger() {
        return Integer.MAX_VALUE;
    }

}

I KNOW BECAUSE I AM AN EXPERT JAVA PROGRAMMER