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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.

NavigableMap clear() Method in Java

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