what does this syntax in Java mean?
<p>I'm a Java newbie and stuck with this:</p>

<pre><code>BufferedReader br1 = new BufferedReader(new InputStreamReader(System.in));
</code></pre>

<p>and</p>

<pre><code>InputStreamReader ISR = new InputStreamReader(System.in);     
BufferedReader BR = new BufferedReader(ISR);
</code></pre>

<ul>
<li><p>What is the difference between them?</p></li>
<li><p>Also, is it compulsory to throw IOException when i'm getting inputs from user?</p></li>
</ul>

<p>thanks.</p>
