How to have a key with multiple values in a map?

Question

I have a map like this

Map map=new HashMap();//HashMap key random order.
map.put(\"a\",10);
map.put(\"a\",20);
map.put(\"a\",30);
map.put(\"b\",10);

System.         


        

Answer 1

Use Map with value type as list of values..For example, in your map, while adding an entry, you will put key as "a" and you will have to add it's value as a list of Integer , having all the required values, like 1,2,3,4.