using a String variable for a name of a HashMap

I am using a while loop to read a set of commands. the command is in the following format : add item price type.
I place the types in a set of Strings, after which if the type does not exist I want to create a new hashmap containing the item(String) and the price(Double). the name of the map should be the type, but it does not allow me to use a String variable for it. Is there a way to get around that?

 while (!input.equals("end")){
            String[] command = input.split(" ");
            if (!categories.contains(command[3])){
                categories.add(command[3]);
                String mapName = command[3];
                Map<String, Double>  mapName = new HashMap<>();
            }
        }

I need the name of the map the be for example shampoos or food or whatever the input was, not mapName.

You will need a map of maps, where the keys of the outter map are the names of the inner maps, like:

Map<String, Map<String, Double>> maps = new HashMap<>();

while (!input.equals("end")){
    String[] command = input.split(" ");
    if (!categories.contains(command[3])){
        categories.add(command[3]);
        String mapName = command[3];
        Map<String, Double>  map = new HashMap<>();
        maps.put(mapName, map);
    }
}

then you can later get the maps by using their name like:

maps.get(<map name>)

No, you can't create variables dynamically in Java.

You will need to create a map of maps:

Map<String,Map<String,Double>> maps = new HashMap<>():

maps.put(mapName, new HashMap<>());

I would be very careful with using maps to store data in your program. Maps are a very bad substitute for classes.

The only case where you should use a map instead of defining a class with fixed field names is if you really don't know the values that will be input. If the input values are known it is almost always better to define classes and parse the input into the class fields.