Java - How to create new Entry (key, value)

Question

I'd like to create new item that similarly to Util.Map.Entrythat will contain the structure key, value.

The problem is that I can't instantiate a Map.Entry because it's an interface.

Does anyone know how to create a new generic key/value object for Map.Entry?

Answer 1

You can just execute the Map.Entry<K, V> interface yourself:

import java.util.Map;

final class MyEntry<K, V> implements Map.Entry<K, V> {

    private final K key;

    private V value;

    public MyEntry(K key, V value) {

        this.key = key;

        this.value = value;

    }

    @Override

    public K getKey() {

        return key;

    }

    @Override

    public V getValue() {

        return value;

    }

    @Override

    public V setValue(V value) {

        V old = this.value;

        this.value = value;

        return old;

    }

}

And then apply it:

Map.Entry<String, Object> entry = new MyEntry<String, Object>("Hello", 123);

System.out.println(entry.getKey());

System.out.println(entry.getValue());