How can I initialize a List Object in java

Question

the return type is List and I declare list for returning and how can I actually declare it after new?

public List<Record> findClosestRecords(int n) throws IndexException {
    if (!sorted || n > records.size()) {

    }
    List<Record> list = new ;
    for (int i = 0; i < n; i++) {
        Record r = this.records.get(i);
        list.add(i, r);
    }
    return list;
}

List is an interface, you need to create an object which implements the interface. Duplicate of: [How to initialize List object in Java?](http://stackoverflow.com/questions/13395114/how-to-initialize-liststring-object-in-java) — mins, Apr 10 '15 at 06:26

score 4 · Answer 1 · answered Apr 10 '15 at 06:25

4

You can try like this:

List<Record> list = new ArrayList<Record>();

Note that List is an interface and you cannot initialize an interface. So you need to create an object which implements the List interface.

answered Apr 10 '15 at 06:25

Rahul Tripathi

168,305
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score 2 · Answer 2 · answered Apr 10 '15 at 06:25

You have to instantiate a concrete implementation of the List interface. The most common one is ArrayList but you can find others in the documentation https://docs.oracle.com/javase/7/docs/api/java/util/List.html

List<Record> list = new ArrayList<Record>();

score 1 · Answer 3 · answered Apr 10 '15 at 06:26

1

List<Record> list = new ArrayList<Record>();

or use diamond syntax;

List<Record> list = new ArrayList<>();

This is implying you implemented the List interface by means of an ArrayList.

answered Apr 10 '15 at 06:26

Jyr

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How can I initialize a List Object in java

3 Answers3