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

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

In Java, you can create a new Map.Entry (key-value pair) using one of the following methods:

  1. Using the AbstractMap.SimpleEntry class (Java 7 and later):

    import java.util.AbstractMap;
import java.util.Map;

// Create a new key-value pair
Map.Entry<String, Integer> entry = new AbstractMap.SimpleEntry<>("myKey", 42);

    In this example, we create a new SimpleEntry with a key of type String ("myKey") and a value of type Integer (42).

  2. Using a custom class that implements the Map.Entry interface:

    You can also create your own custom class that implements the Map.Entry interface and define the key and value types as per your requirements. Here's an example:

    public 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 newValue) {
        V oldValue = value;
        value = newValue;
        return oldValue;
    }
}

// Create a new key-value pair using your custom entry class
Map.Entry<String, Integer> entry = new MyEntry<>("myKey", 42);

    In this example, we create a custom MyEntry class that implements the Map.Entry interface and provides its own implementation for getKey(), getValue(), and setValue() methods.

Both of these methods allow you to create new key-value pairs (entries) in Java. You can choose the method that best suits your needs and the level of customization required for your key-value pairs.

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