I want to use a `HashMap` to store multiple values per key.

I think I have figured out what is wrong with my code, but I don't know how to fix it. As I've understood, everytime the method get sent new arguments, the HashMap overwrites itself instead of adding a new value. 

How can I stop it from overwriting itself, and instead add a new title.

```
HashMap<String, List<String>> owner = new HashMap<String, List<String>>();

    public void Owner (String name, String title) throws Exception{
        List<String> listTitle = new ArrayList<String>();
        if(!listTitle.contains(title)){
            listeTitle.add(title);
        }
        else if(listeTitle.contains(title)){
            System.out.println("This person allready owns this title.");
        }
        eier.put(name, listTitle);
    }

```

The method used to print the HashMap:

```
public void PrintOwner(){
    for (HashMap.Entry<String, List<String>> entry : owner.entrySet()) {
        String key = entry.getKey();
        List<String> values = entry.getValue();
        System.out.println(key + " owns:" + values;
    }  
}

```

Example of how I would like the console to look like after running:

> 
> **Jon owns:**
> 
> 
> [Lord of the Rings]
> 
> 
> [Harry Potter]
> 
> 
> **Dave owns:**
> 
> 
> [The Martian]
> 
> 
> [Frozen]
> 
> 
> 

But currently it only shows:

> 
> **Jon owns:**
> 
> 
> [Harry Potter]
> 
> 
> **Dave owns:**
> 
> 
> [Frozen]
> 
> 
>