Unmix My Strings

UnmixStrings.java

public class UnmixStrings {
    public static void main(String[] args) {
        System.out.println(String.format("Input: hTsii  s aimex dpus rtni.g, Output: %s",unmix("hTsii  s aimex dpus rtni.g")));
        System.out.println(String.format("Input: 214365, Output: %s",unmix("214365")));
        System.out.println(String.format("Input: badce, Output: %s",unmix("badce")));
    }
    public static String unmix(String str) {
        StringBuilder sb = new StringBuilder();
        int length = str.length();
        boolean oddLength = !(length%2==0);
        int i=0;
        for(;i<length-1;i=i+2)
        {
            sb.append("" + str.charAt(i + 1) + str.charAt(i));
        }
        if (oddLength) {
            sb.append(str.charAt(i));
        }
        return sb.toString();
    }
}