title: += operator not working with string
body: <p>I'm trying to produce a program that outputs the user's input in a form like this:</p>
  
  <p>input: word</p>
  
  <p>w</p>
  
  <p>wo</p>
  
  <p>wor</p>
  
  <p>word</p>
  
  <p>This incremental build-up doesn't seem to be working. </p>
  
  <pre><code>import java.util.*;
  public class SpellMan {
  public static void main(String[] args) {
      Scanner kb = new Scanner (System.in) ;
      System.out.println("Give me a word &gt; ");
      String word = kb.nextLine();
      for(int i = 0; i&lt; word.length();i++){
          String bword += ""+word.charAt(i); 
  
          System.out.println(bword);
      }
  }
  }
  </code></pre>