Java: Putting items from List into HashMap efficiently [duplicate]

Question

I have a list here:

List<QueryStrings> queryStrings

and QueryStrings is just a simple class

public class QueryStrings {
    private Integer id;
    private String rel;
    private String impl;
}

I need to put the List into a HashMap where the id will be the key, I am doing it like this right now, looping the List one item at a time:

HashMap<Integer, QueryStrings> queryMap = new HashMap<>();
for (QueryStrings element : queryStrings) {
    Integer thisId = Integer.parseInt(element.getId());
    queryMap.put(thisId, element);
}

Is there a better way to this? I do not want to loop each items, is that possible?

Edit:

Sorry I should not parse the integer, so the code should look like:

HashMap<Integer, QueryStrings> queryMap = new HashMap<>();
for (QueryStrings element : queryStrings) {
    queryMap.put(element.getId(), element);
}

Answer 1

Don't parse the int's if it's already an int!

HashMap<Integer, QueryStrings> queryMap = new HashMap<>();
for (QueryStrings element : queryStrings) {
    queryMap.put(element.getId(), element);
}

That said, if it's Java 8 you can have more concise syntax, although the performance differences are minimal.

list.stream().collect(Collectors.toMap(QueryStrings::getId, Function.identity()));