How to add an object to pair of pair list in Java?
<p>the list type:</p>

<pre><code>List&lt;Pair&lt;Integer, Pair&lt;Integer, Integer&gt;&gt;&gt; listPairOfPair = null;
</code></pre>

<p>I tried these but it didn't work:</p>

<pre><code>listPairOfPair.add(new Pair&lt;Integer, Pair&lt;Integer, Integer&gt;&gt;(1, (2,3));

listPairOfPair.add(new Pair&lt;Integer, Pair&lt;Integer, Integer&gt;&gt;(1, Pair.create(2,3)));
</code></pre>