Why two if statements that are logically similar showing different outputs,below are two if statements which got me confused

Question

Here the pattern is a string and arr is an array of strings, and map here is a hashmap i.e HashMap<Character,String> map = new HashMap<>();

if (!map.get(pattern.charAt(i)).equals(arr[i]) {
    return false;
}

The above one is working. But what is wrong with the next one?

if (map.get(pattern.charAt(i))!=(arr[i])){
    return false;
}

This is a part of my solution for question no. 290 leetcode. When I use first if statement the whole code is working, but for the second version of if statement not all test cases are getting passed. Why so?

class Solution {
    public boolean wordPattern(String pattern, String s) {
        String[] arr=s.split(" ");
        if (arr.length!=pattern.length()) {
            return false;
        }
        HashMap<Character,String> map = new HashMap<>();
        for (int i=0;i<arr.length;i++) {
            if (map.containsKey(pattern.charAt(i))){
                //**this line is my doubt**//
                if (!map.get(pattern.charAt(i)).equals(arr[i])){
                    return false;
                } else {
                    if (map.containsValue(arr[i])) {
                        return false;
                }
                 map.put(pattern.charAt(i),arr[i]);
            }
        }
        return true;
    }
}