Read words until user writes 'end', then, order lexicographically(as in a dictionary), show the last word

User will enter words until the last word written is "end", then the code has to order lexicographically, as we have in a dictionary, all the words entered before 'end' and print the last word, the one classified the last.

//.....

    Scanner word = new Scanner (System.in);
    String keyword="end";
    String finalstring;

    String[] firststring= new String[1000]; //Don't know how to stablish a //dynamic string[] length, letting the user stablish the string[].length  
    for(int c=0;c<firststring.length;c++){
        firststring[c]=word.next();
        if(firststring[c].equals(keyword)){
            finalstring=firststring[c].substring(0,c);
            c=cadena.length-1; //To jump out of the for.
        }
    }
    for (int c=0;c<finalstring.length();c++) {
        for(int i=c+1;i<finalstring.length();i++) {
            if (firststring[c].compareTo(firststring[i])>0) {
                String change = firststring[c];
                firststring[c] = firststring[i];
                firststring[i] = change;
            }
        }
    }
    System.out.print("\nYou entered "end" and the last word classified is "+finalstring[finalstring.length()-1]); //Of course, error here, just did it to put one System.out.print of how should the result be.
}

}

This is what I tried, though, without any type of success, any help of yours will be a big help, thank you ALL!