Java HashMap put() Method
Example
Add entries into a map:
import java.util.HashMap;
public class Main {
public static void main(String[] args) {
HashMap<String, String> capitalCities = new HashMap<String, String>();
capitalCities.put("England", "London");
capitalCities.put("Germany", "Berlin");
capitalCities.put("Norway", "Oslo");
capitalCities.put("USA", "Washington DC");
System.out.println(capitalCities);
}
}
Definition and Usage
The put() method writes an entry into the map. If an entry with the same key already exists then the value of that entry will be changed.
Syntax
public V put(K key, V value)K and V refer to the data types of the keys and values of the map.
Parameter Values
| Parameter | Description |
|---|---|
| key | Required. The key of the map entry. |
| value | Required. The value of the map entry. |
Technical Details
| Returns: | If an entry already existed with the specified key then it returns the value of that entry before overwriting it, otherwise it returns null. |
|---|
Related Pages
❮ HashMap Methods
