Get substring from parenthesis JAVA : <p><strong>No full solutions please!</strong></p>

<blockquote>
  <blockquote>
    <p>Given a string that contains a single pair of parenthesis, compute recursively a new string made of only of the parenthesis and their
    contents, so "xyz(abc)123" yields "(abc)".</p>
  </blockquote>
  
  <p>parenBit("xyz(abc)123") → "(abc)" </p>
  
  <p>parenBit("x(hello)") → "(hello)"</p>
  
  <p>parenBit("(xy)1") → "(xy)"</p>
</blockquote>

<p>My solution doesn't work</p>

<pre><code>public String parenBit(String str) {
        char c;
        int start = 0;
        int end = 0;
        for(int i=0; i &lt; str.length(); i++){
            c = str.charAt(i);
            if(c == '('){
                start = i;

            } if(c == '('){
                end = i;
                return str.substring(start, end);
            }

        }

return "andrew";
}
</code></pre>

<p>It doesnt print out anything. Why?</p>
