Java – Printing commas in a loop

I’m running into this problem where if want to loop through an array and print out its contents separated by a comma, it prints out an extra at the end.
I did some searching but, couldn’t find an answer that worked for this situation.

Code:

public String toString(){

    String hold= "";
    for(int i = 0; i < array.length; i ++){

        if(array[i] == true){
            hold + = i;
            if(i != array.length-1)
                hold+= ",";
        }
    }
    return hold;
}