Java HashMap containsKey() Method
Example
Check if a key exists in 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.containsKey("England"));
System.out.println(capitalCities.containsKey("Canada"));
}
}
Definition and Usage
The containsKey() method returns true if an entry with the specified key exists in the map and false otherwise.
Syntax
public boolean containsKey(Object key)Parameter Values
| Parameter | Description |
|---|---|
| key | Required. The key to search for. |
Technical Details
| Returns: | true if an entry with the specified key exists in the map, false otherwise. |
|---|
Related Pages
❮ HashMap Methods
