Find all substrings that are palindromes

Question

If the input is \'abba\' then the possible palindromes are a, b, b, a, bb, abba.
I understand that determining if string is palindrome is easy. It would be like:

Answer 1

I tried the following code and its working well for the cases Also it handles individual characters too

Few of the cases which passed:

abaaa --> [aba, aaa, b, a, aa] 
geek  --> [g, e, ee, k] 
abbaca --> [b, c, a, abba, bb, aca] 
abaaba -->[aba, b, abaaba, a, baab, aa] 
abababa -->[aba, babab, b, a, ababa, abababa, bab] 
forgeeksskeegfor --> [f, g, e, ee, s, r, eksske, geeksskeeg, 
                      o, eeksskee, ss, k, kssk]

Code

static Set set = new HashSet(); 
static String DIV = "|";

public static void main(String[] args) {
    String str = "abababa";
    String ext = getExtendedString(str);

    // will check for even length palindromes
    for(int i=2; i ext.length()-1) {
        return;
    }
    if (ext.charAt(mid-offset) == ext.charAt(mid+offset)) {
        set.add(ext.substring(mid-offset, mid+offset+1).replace(DIV, ""));
        addPalindromes(mid, offset+2, ext);
    }
}

Hope its fine