title: Java, How to add values to Array List used as value in HashMap
body: <p>What I have is a <code>HashMap&lt;String, ArrayList&lt;String&gt;&gt;</code> called <code>examList</code>. What I want to use it for is to save grades of each course a person is attending. So key for this <code>HashMap</code> is <code>couresID</code>, and value is a <code>ArrayList</code> of all grades (exam attempts) this person has made.</p>
  
  <p>The problem is I know how to work with array lists and hashmaps normally, but I'm not sure how to even begin with this example. So how would I, or example, add something to <code>ArrayList</code> inside <code>HashMap</code>?</p>