Last Updated : 31 Oct, 2018
The clear() method of NavigableMap interface in Java is used to clear and remove all of the elements or mappings from a specified Map.
Syntax:NavigableMap.clear()Parameters:
The method does not accept any parameters.
Return Value:The method does not return any value. Below programs are used to illustrate the working of clear() method:
Program 1:Mapping String Values to Integer Keys.
Java
// Java code to illustrate the clear() method
import java.util.*;
public class NavigableMap_Demo {
public static void main(String[] args)
{
// Creating an empty NavigableMap
NavigableMap<Integer, String> nav_map = new TreeMap<Integer, String>();
// Mapping string values to int keys
nav_map.put(10, "Geeks");
nav_map.put(15, "4");
nav_map.put(20, "Geeks");
nav_map.put(25, "Welcomes");
nav_map.put(30, "You");
// Displaying the NavigableMap
System.out.println("Initial Mappings are: " + nav_map);
// Clearing the tree map using clear()
nav_map.clear();
// Displaying the final NavigableMap
System.out.println("Finally the map looks like: " + nav_map);
}
}
Output:
Initial Mappings are: {10=Geeks, 15=4, 20=Geeks, 25=Welcomes, 30=You}
Finally the map looks like: {}
Program 2:
Mapping Integer Values to String Keys.
Java
// Java code to illustrate the clear() method
import java.util.*;
public class NavigableMap_Demo {
public static void main(String[] args)
{
// Creating an empty NavigableMap
TreeMap<String, Integer> nav_map = new TreeMap<String, Integer>();
// Mapping int values to string keys
nav_map.put("Geeks", 10);
nav_map.put("4", 15);
nav_map.put("Geeks", 20);
nav_map.put("Welcomes", 25);
nav_map.put("You", 30);
// Displaying the NavigableMap
System.out.println("Initial Mappings are: " + nav_map);
// Clearing the tree map using clear()
nav_map.clear();
// Displaying the final NavigableMap
System.out.println("Finally the map looks like: " + nav_map);
}
}
Output:
Initial Mappings are: {4=15, Geeks=20, Welcomes=25, You=30}
Finally the map looks like: {}
Note:
The same operation can be performed with any type of Mapping with variation and combination of different data types.
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