Flash cards
Review the key moves
1/4
Core idea
What is the main idea behind Java HashMap replaceAll() 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 replaceAll() method replaces the value of every entry in the map with the result of an operation using the entry's key and value.
Definition and Usage
Java HashMap replaceAll() 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");
capitalCities.replaceAll((k, v) -> "The capital of " + k + " is " + v);
System.out.println(capitalCities);
}
}Definition and Usage
The replaceAll() method replaces the value of every entry in the map with the result of an operation using the entry's key and value. The operation can be defined by a lambda expression that is compatible with the apply() method of Java's BiFunction interface.
To learn about lambda expressions, see our Java Lambda Expression tutorial .
Syntax
public void replaceAll(BiFunction
operator )Parameter Values
| Parameter | Description |
|---|---|
| operator | Required. A BiFunction object or lambda expression which operates on each entry. The first parameter of the function contains the key of an entry and the second parameter contains its value. |