How do String objects work (like immutable objects)?
<p>I have these two situations:</p>

<pre><code>String s = "aa";
s = s + " aa";
    System.out.println(s);
    //......
</code></pre>

<p>that work fine! It prints <b>aa aa</b>.
But there is a problem:</p>

<pre><code>String s = "aa";
this.addStringToStatement(s, " aa");
System.out.println(s);
//...
private void addStringToStatement(String statement, Object value) {
    statement += value;
}
</code></pre>

<p>It prints: <b>aa</b>.
What is the reason??
Thanks!</p>
