public static void main(String[] args) {

// TODO Auto-generated method stub

List<String> list = letterCombinations("2");

for (String s : list)

System.out.println(s);

}

static String word[][] = { { "a", "b", "c", "" }, { "d", "e", "f", "" }, { "g", "h", "i", "" },

{ "j", "k", "l", "" }, { "m", "n", "o", "" }, { "p", "q", "r", "s" }, { "t", "u", "v", "" },

{ "w", "x", "y", "z" } };

public static List<String> letterCombinations(String digits) {

List<String> ans = new ArrayList<String>();

if (digits.equals(""))

return ans;

int[] iArr = new int[digits.length()];

for (int i = 0; i < digits.length(); i++) {

char c = digits.charAt(i);

if (c == '1')

return ans;

iArr[i] = c - '2';

}

search(ans, "", iArr, 0);

return ans;

}

public static void search(List<String> ans, String temp, int[] iArr, int cur) {

if (cur == iArr.length) {

ans.add(temp);

return;

}

for (String s : word[iArr[cur]]) {

if (s.equals(""))

continue;

else {

temp += s;

search(ans, temp, iArr, ++cur);

temp = temp.substring(0, --cur);

}

}

}