CODEWITHSUNDEEP
javahashmap
Zahir Abas
Zahir Abas

Reputation: 143

Exception while Populating Hash Map

Class Test is my separate class which has two field of String and Float type, I am using this class with List Collections which will be finally populated as values into HashMap.

But when I try to populate the Map with a key and the List objects (values) into the map, Java does not seem to accept it as it is not valid syntax: 

ArrayList <Test> list = new ArrayList <Test> ();

Map<Integer, ArrayList <Test>> mp = new HashMap<Integer, ArrayList <Test>>();  

list.add(new Telephone ( 0.9 , "A"));
list.add(new Telephone(5.1 , "A"));

mp.put(0,list.get(0)); // this Does Not work :(, it should work

Output:

Exception in thread "main" java.lang.Error: Unresolved compilation problem: 
The method put(Integer, ArrayList<Telephone>) in the type  
   Map<Integer,ArrayList<Telephone>> is not applicable for the arguments 
   (int,   Telephone) at Main.main(Main.java:64)

Upvotes: 0

Views: 223

Answers (3)

Vishal K
Vishal K

Reputation: 13066

Going by your requirement you told in comments and question above I think you need following syntax for Map declaration:

Map<Integer,Test> mp = new HashMap<Integer,Test>();

EDIT

OK here is the Edit:

ArrayList<Test> list = new ArrayList<Test>();
Map<Integer,ArrayList<Test>> mp = new HashMap<Integer,ArrayList<Test>>();
list.add(new Test(0.1,"A"));
list.add(new Test(0.2,"B"));
mp.put(1,list);

and if you again want to put more Test objects at key 1 then do as follows:

List<Test> value = mp.get(1);
value.add(0.3,"c");
value.add(0.5,"E");

mp.put(1,value);

Upvotes: 2

Renjith
Renjith

Reputation: 3274

Your map accepts an Integer as key and ArrayList of Test as value.But instead of arrayList of Test object, you are trying to put Telephone object. Your IDE is clearly stating that.

Map<Integer,ArrayList<Telephone>> is not applicable for the arguments 
   (int,   Telephone) at Main.main(Main.java:64)

Upvotes: 2

Andremoniy
Andremoniy

Reputation: 34900

You map can accept only List objects as values, while you are trying to put there simple Telephone object.

Upvotes: 1

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