How do I add multiple values to the same key in a TreeMap?

Question

My tree Map is

Map<String, Double> restrMap = new TreeMap<String, Double>(); 

While adding the below two value to the treeMap, it only shows one. The second value, when comes updates the first one.

6, 8.00
6, 5.00

How can I add two values for the same key, perhaps in different rows?

Answer 1

If you are adding multiple values to the same key, consider having a Map of Lists.

Map<String, List<Double>> restrMap = new TreeMap<String, List<Double>>();