Flash cards
Review the key moves
1/4
Core idea
What is the main idea behind Java HashMap containsKey() Method?
Lesson checks
Practice each idea before moving on
Short Mimo-style checks built from this lesson's code, terms, and sequence.
1Quick choice
Which statement best captures the main point of this lesson?
2Fill blank
Complete the missing token from the example code.
___ java.util.HashMap;3Order
Put the learning moves in the order that makes the concept easiest to apply.
The containsKey() method returns true if an entry with the specified key exists in the map and false otherwise.
Definition and Usage
Java HashMap containsKey() Method
❮ HashMap Methods
Example
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. |
|---|