Computing Levenshtein Distance in Java

public class LevenshteinDistance {
 
 private static int minOfThree(int a, int b, int c) {
 return Math.min(a, Math.min(b, c));
 }
 
 private static int calculateCost(char s, char t) {
 return s==t?0:1;
 }
 
 private static int[][] initializeMatrix(int s, int t) {
 int[][] matrix = new int[s + 1][t + 1];
 for (int i = 0; i <= s; i++) {
 matrix[i][0] = i;
 }
 
 for (int j = 0; j <= t; j++) {
 matrix[0][j] = j;
 }
 return matrix;
 }
 
 public static int computeLevenshteinDistance(final String s, final String t) {
 
 char[] s_arr = s.toCharArray();
 char[] t_arr = t.toCharArray();		
 
 if(s.equals(t)) { return 0; }
 if (s_arr.length == 0) { return t_arr.length;}
 if (t_arr.length == 0) { return s_arr.length;}
 
 int matrix[][] = initializeMatrix(s_arr.length, t_arr.length);
 
 for (int i = 0; i < s_arr.length; i++) {
 for (int j = 1; j <= t_arr.length; j++) {
    matrix[i+1][j] = minOfThree(matrix[i][j] + 1,	
        matrix[i+1][j - 1] + 1, 
        matrix[i][j - 1] + calculateCost(s_arr[i], t_arr[j-1]));
 }
 }
 
 return matrix[s_arr.length][t_arr.length];
 }
 
}