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Java HashMap isEmpty() Method

Flash cards

Review the key moves

1/4
Core idea

What is the main idea behind Java HashMap isEmpty() 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 isEmpty() method returns true if the map has no entries and false otherwise.
Definition and Usage
Java HashMap isEmpty() 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>();
    System.out.println(capitalCities.isEmpty());
    capitalCities.put("England", "London");
    capitalCities.put("Germany", "Berlin");
    capitalCities.put("Norway", "Oslo");
    capitalCities.put("USA", "Washington DC");
    System.out.println(capitalCities.isEmpty());
  }
}

Definition and Usage

The isEmpty() method returns true if the map has no entries and false otherwise.

Syntax

public boolean isEmpty()

Technical Details

Returns:true if the map has no entries and false otherwise.

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Java HashMap keySet() Method