Mapping Multiple Values to a Single Key in HashMap

In Java's HashMap, each key is associated with a single value. However, there are scenarios where you may need to map multiple values to a single key. Here's how you can achieve this:

The MultiValueMap Approach:

The simplest and most straightforward approach is to use a Map of List. This involves creating a HashMap where the values are ArrayLists containing multiple values. For instance:

Map

To add multiple values for a specific key, you can use the put() method:

multiMap.put("key", new ArrayList

To retrieve the values, you can use the get() method to obtain the ArrayList and then iterate over it:

List

In this example, values will contain a List with ["value1", "value2", "value3"]. You can then access the desired value based on its index (i.e., values.get(2) for the third value).