Given two strings, how do we check if their edit distance is 1?

CheckEditDistance1.java

import java.util.Scanner;

public class Solution {
    public static void main(String []args) {
        Scanner reader = new Scanner(System.in);
        String str1 = reader.nextLine();
        String str2 = reader.nextLine();
        if(hasEditDistance1(str1, str2))
            System.out.println("Yes");
        else
            System.out.println("No");
    }

    public static boolean hasEditDistance1(String str1, String str2) {
        if( Math.abs(str1.length()-str2.length()) > 1)
            return false;
        int i, j;

        if(str1.length() == str2.length()) {
            int mismatches = 0;
            for(i = 0; i < str1.length(); i++) {
                if(str1.charAt(i) != str2.charAt(i))
                    mismatches++;
                if(mismatches > 1) {
                    return false;
                }
            }
            return mismatches == 1;
        }
        //Make sure str1 is shorter string
        if(str1.length() > str2.length()) {
            String temp = str1;
            str1 = str2;
            str2 = temp;
        }

        int matched = 0;
        for(i = 0, j = 0; i < str1.length() && j < str2.length(); ) {
            if(str1.charAt(i) == str2.charAt(j)) {
                i++;
                j++;
                matched++;
            } else {
                j++;

            }
        }
        return matched == str1.length();
    }
}