How to correctly use HashMap?

Question

HashMap savedStuff = new HashMap();
savedStuff.put("symbol", this.symbol); //this is a string
savedStuff.put("index", this.index); //this is an int

gives me the warning:

HashMap is a raw type. References to generic type HashMap<K,V> should be parameterized  

Answer 1

This is simple code for use of hashmap. There i will use key as integer and value as string type. Map is very useful when our functionality works on key and values pairs. Below is a simple example of use hashmap. I hope it is very useful for all.

public class CreateHashMap {

    public static void main(String[] args) {

    Map<Integer,String> map = new HashMap<Integer,String>();

    /*
     * Associates the specified value with the specified key in 
       this map (optional operation). If the map previously 
       contained a mapping for the key, the old value is 
       replaced by the specified value
     */
        map.put(1,"ankush");
        map.put(2, "amit");
        map.put(3,"shivam");
        map.put(4,"ankit");
        map.put(5, "yogesh");

        //print hashmap
        System.out.println("HashMap = "+map);


    }

}

Reference : create and use of map