remove()

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.remove("USA");
    capitalCities.remove("Germany", "Berlin");
    capitalCities.remove("England", "Cambridge");

    System.out.println(capitalCities);
  }
}

public V remove(Object key)

public boolean remove(Object key, Object value)