java - Logical issue with loops -

i'm making programm takes sentence input, creates array of these words , displays wether word redundant or isn't.

if "hello hi hello" scanned, program should advert user there's redundancy.

public static void main(string[] args)  {     scanner sc = new scanner(system.in);     string sentence ;     system.out.println("enter sentence :");     sentence = sc.nextline();     string[] t = sentence.split(" "); //split sentence @ each " " array      int i=0, o=0 ; //iterators      boolean b=false; //redundancy condition      for(string s : t) // each string of t     {         system.out.println("t["+i+"] = "+ s);          while(b) //while there's no redundancy         {             if(o!=i) //makes sure strings not @ same index.             {                  if(s==t[o])                 {                     b=true; //redundancy true, while stops                 }             }             o++;         }         i+=1;     }      if(b)        {         system.out.println("there identical words.");     }     else     {         system.out.println("there no identical words.");     }  } 

here working code -

        while(o<t.length && !b)         {             if(o!=i)             {                  if(s.equals(t[o]))                 {                     b=true;                 }             }             o++;         }         i+=1;     }