Create a list of key value objects

Question

I am trying to create a list of key-value pairs. Here is what I have so far:

Map<Integer,String> map = new HashMap<Integer,String>().put(songID, songList.get(i).name);

This gives me the following error:

Type mismatch: cannot convert from String to Map

Also, how would I iterate through these? Thanks!

Answer 1

When you call put on the map of type Map <Integer,String>, you will get the String returned. So when you do this:

new HashMap<Integer,String>().put(songID, songList.get(i).name);

it will return a String

and when you try to assign it to a map

Map<Integer,String> map 

compiler throws an error,

Type mismatch: cannot convert from String to Map

Here is the signature of put method form javadocs:

public V put(K key,
             V value)

you need to break down the this complex problematic statement:

Map<Integer,String> map = new HashMap<Integer,String>().put(songID, songList.get(i).name);

to something like:

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

map.put(songID, songList.get(i).name);

Answer 2

The answer on this thread: Java HashMap associative multi dimensional array can not create or add elements

has an example of how to do this.