Storing a new object as the value of a hashmap?

Question

I am trying to find a way to store a new instance of a class as the value in a Java hashmap. The idea was given to me by a Java instructor in order to create a data storage

Answer 1

The problem is that your code only specifies that the values in the map are Object. You know more than that, so tell the compiler that information:

HashMap mapper = new HashMap();
mapper.put("NS01", new InfoStor("NS01"));
...

InfoStor value = mapper.get("NS01");
Integer memory = value.getMemory();

Note that it's generally though not always better to use interfaces for the variable types - and you can use the diamond operator for the constructor call, letting the compiler use type inference to fill in the type arguments:

Map mapper = new HashMap<>();
mapper.put("NS01", new InfoStor("NS01"));
...

InfoStor value = mapper.get("NS01");
Integer memory = value.getMemory();