Pangram : Problem on hackerrank

This is a problem mentioned on Hackerrank. Below is my attempt to solve this problem.

Problem Statement

Roy wanted to increase his typing speed for programming contests. So, his friend advised him to type the sentence "The quick brown fox jumps over the lazy dog" repeatedly because it is a pangram. ( pangrams are sentences constructed by using every letter of the alphabet at least once. )
After typing the sentence several times, Roy became bored with it. So he started to look for other pangrams.
Given a sentence s, tell Roy if it is a pangram or not.

import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        char[] str = in.nextLine().toCharArray();
        boolean[] resultArr = new boolean[26];
int smallMax = 'z';
int capMax = 'Z';

for (int i = 0; i < str.length; i++) {
if (str[i] >= 'a' && str[i] <= 'z') {
resultArr['z' - str[i]] = true;
} else if (str[i] >= 'A' && str[i] <= 'Z') {
resultArr['Z' - str[i]] = true;
}
}
boolean flag = true;
for (int j = 0; j < resultArr.length; j++) {
if (resultArr[j] == false) {
flag= false;
break;
}
}
if(flag == true){
System.out.println("pangram");
}else{
System.out.println("not pangram");
}

    }
}