Create lists with java

You have to create an Item class, that's the whole point of OOP!

Very minimal example:

public class Item {
    public String ref;
    public int size;
    public int date;
    public Item(String ref, int size, int date) {
        this.ref = ref;
        this.size = size;
        this.date = date;
    }
}

Then it's just a List<Item> and you can access each part with myList.get(i).ref etc:

List<Item> l = new ArrayList<>();
l.add(new Item("GH987", 22, 1992));
l.add(new Item("98KJ", 27, 2000));
...
for (Item it : l)
    System.out.println("Ref: "+item.ref+", size: "+item.size+", date: "+item.date);

Now, if you really want to use a Map to store each attribute, you have to think what would be your unique key. Let's suppose it's ref, which is a String:

Map<String,Integer> sizes = new LinkedHashMap<>(); // LinkedHashMap keeps the insert order
Map<String,Integer> dates = new LinkedHashMap<>();

sizes.put("GH987", 22);
dates.put("GH987", 1992);
sizes.put("98KJ", 27);
dates.put("98KJ", 2000);

then it's difficult to access all members as they're not bundled in a single instance:

String ref = "GH987";
System.out.println("Ref: "+ref+", size: "+sizes.get(ref)+", date: "+dates.get(ref))

Here you should realize that if a Map hasn't been updated, it will return null on the value and you'll have to handle consistency yourself. It is also a pain to create so many objects just to store single attributes, which in your case are Number subclasses (e.g. Integer) instead of native types, which are far more efficient.

So do yourself a favor, and create your Item class. Then you can use a Map to quickly access a particular item based on its key, which looks like the ref member:

myMap.put(ref, new Item(ref, size, date));
Item it = myMap.get(ref);
...