reverse vowels of string

class Solution {
    public String reverseVowels(String s) {
        char[] arr= s.toCharArray();
        int start=0;
        int end= arr.length-1;
        while(end>start){
            boolean leftIsVowel= isVowel(arr[start]);
            boolean rightIsVowel= isVowel(arr[end]);
            if(leftIsVowel && rightIsVowel){
                swap(start, end, arr);
                start++;
                end--;
            }else if(leftIsVowel){
                end--;
            }else start++;
        }
        return new String(arr);
    }
    
    public void swap(int start, int end, char[] arr){
        char temp= arr[start];
        arr[start]= arr[end];
        arr[end]= temp;
    }
    public boolean isVowel(char ch){
        ch= Character.toLowerCase(ch);
        if(ch=='a'|| ch=='e'|| ch=='i'|| ch=='o' || ch=='u') return true;
        return false;
    }
}