split a long string but not in the middle of a word

string_nice_split.java

private String[] split_string(String newQuestion){
        /*
        this:
        "According to Ruzbihan, these 2 tribe
        s were part of both uzbek and mangits"
        
        must be:
        "According to Ruzbihan, these 2 tribes 
        were part of both uzbek and mangits"
        
        */
        String[] words = newQuestion.split(" ");
        String first_part = "";
        String second_part = "";
        int size = 0;
        for(int i = 0; (first_part.length() + words[i].length()) < newQuestion.length()/2 ; i++) {
            size++;
            first_part += words[i] + " ";
        }
        for(int j = size; j < words.length; j++) {
            second_part += words[j] + " ";
        }
        return new String[]{first_part,second_part};
    }