Adding elements to different collections in a single lambda expression : <p>I possibly use the wrong terms, feel free to correct.</p>

<p>I have a test method which takes a <code>Runnable</code>:</p>

<pre><code>void expectRollback(Runnable r) { .. }
</code></pre>

<p>I can call this method like this:</p>

<pre><code>expectRollback(() -&gt; aList.add(x))
</code></pre>

<p>Cool, I understand lambdas! This is awesome. Let's be super clever...</p>

<pre><code>expectRollback(() -&gt; aList.add(x) &amp;&amp; bList.add(y))
</code></pre>

<p>But what? That doesn't compile: <code>'void' methods cannot return a value.</code> Doesn't the first call also return a value though? What is the difference between the first and the second call?</p>
