How can I add up all the Values of a List<Integer> if its a value in a map? : <p>So, basically I have a map that looks like :</p>

<p><code>Map&lt;String, List&lt;Integer&gt;&gt; map = new HashMap&lt;&gt;();</code></p>

<p>I also have a method that needs to add up all those values for a certain key:</p>

<p><code>public Integer getTotalPointsForStudent(String student) {
}</code></p>

<p>How can I add up all the Values of the List assigned to a certain "student"?</p>

<p>Thanks in advance.</p>
