How to get values from a Map with different value types? (Java)

Question

I have a utility function that returns Map, but that Map always has this structure:

{ \"a\": , \"b\"         


        

Answer 1

You need to cast the Object retrieved from Map to the type you required:

Type1 type1obj = (Type1) data.get("a");

But with the code above you have to make sure the type of value associated with key "a" is Type1, otherwise a ClassCastException will thrown at runtime.

If you cannot guarantee the type of the Object retrieved, you can check it like:

Object obj = data.get("a");
Type1 type1obj;
if(obj instanceof Type1) {
    type1obj = (Type1) obj;
} else {
    //to print error log or do some workaround
}