Java implementation of Levenshtein distance. Follows a lot of "clean code" principles I learnt from Robert C Martin's book Chapters 1-4.

EditDistance.java

import java.util.ArrayList;
import java.util.Scanner;

public class EditDistance {
    private static final int INSERT_COST = 1;
    private static final int DELETE_COST = 1;
    private static final int SUBST_COST = 2;

    private static int[][] distances;
    private static String fromString;
    private static String toString;


    public static int getDistance(String fromString, String toString) {
        EditDistance.fromString = fromString;
        EditDistance.toString = toString;

        int fromLength = fromString.length();
        int toLength = toString.length();

        initializeDistances(fromLength, toLength);

        for (int i = 1; i <= fromLength; i++) {
            for (int j = 1; j <= toLength; j++) {
                calculateDistance(i, j);
            }
        }

        return distances[fromLength][toLength];
    }


    private static void initializeDistances(int fromLength, int toLength) {
        distances = new int[fromLength+1][toLength+1]; // index range [0-fromLength][0-toLength]
        for (int i = 0; i <= fromLength; i++) {
            distances[i][0] = i;
        }
        for (int j = 0; j <= toLength; j++) {
            distances[0][j] = j;
        }
    }


    private static void calculateDistance(int from, int to) {
        int delCost = getDeleteCost(fromString.charAt(from-1))  +  distances[from-1][to]; // deleting the last character
        int insCost = getInsertCost(toString.charAt(to-1))      +  distances[from][to-1]; // adding a character at the end
        int subCost = getSubstCost(fromString.charAt(from-1), toString.charAt(to-1)) + distances[from-1][to-1]; // replacing the last character

        distances[from][to] = getMinimum(delCost, insCost, subCost);
    }


    private static int getDeleteCost(char charToDelete) {
        return DELETE_COST;
    }


    private static int getInsertCost(char charToInsert) {
        return INSERT_COST;
    }


    private static int getSubstCost(char fromChar, char toChar) {
        if (fromChar == toChar) return 0;
        else return SUBST_COST;
    }


    private static int getMinimum(int a, int b, int c) {
        if (a < b) {
            if (a < c) return a;
            else return c;
        }
        else {
            if (b < c) return b;
            else return c;
        }
    }



    public static void main(String[] args) {
        char again = 'n';
        Scanner sc = new Scanner(System.in);

        String fromString;
        String toString;

        do {
            System.out.print("Enter source string:");
            fromString = sc.nextLine();
            System.out.print("Enter destination string:");
            toString = sc.nextLine();
            System.out.println("Computing for " + fromString + " and " + toString + ":");
            System.out.println(EditDistance.getDistance(fromString, toString));
            System.out.print("\nGo again? (y/n)");
            again = sc.next().charAt(0);
            sc.nextLine(); // clearing scanner buffer
        }
        while (again == 'y');

        sc.close();
    }
}