java - Binary searching for string arrays -

how sort array of string binary search. below recieve minus number index instead of correct index. please help? if word not in array -1 should returned.

  public static int binary (string [] theword, string a) {     int index = -1;         arrays.sort(theword);         arrays.tostring(theword);         index = arrays.binarysearch(theword, a);     return index;  }    

it works, see below

public static void main(string... args) {      string words[] = { "abc3", "abc2", "abc1", "abc4" };      arrays.sort(words);     system.out.println(arrays.tostring(words));     {         string word = "abc3";         int index = arrays.binarysearch(words, word);         index = index >= 0 ? index : -1;         system.out.println(word + " = " + index);     }     {         string word = "abc11";         int index = arrays.binarysearch(words, word);         index = index >= 0 ? index : -1;         system.out.println(word + " = " + index);     } } 

output

[abc1, abc2, abc3, abc4] abc3 = 2 abc11 = -1 

you return index sorted array while need index original array.