SortedMap remove() method in Java with Examples

The remove() method of SortedMap interface in Java is used to remove the mapping for a key from this map if it is present in the map. 

Syntax: 

V remove(Object key)

Parameters: This method has the only argument key whose mapping is to be removed from the map.

Returns: This method returns the value to which this SortedMap previously associated the key, or null if the SortedMap contained no mapping for the key.

Note: The remove() method in SortedMap is inherited from the Map interface in Java.

Below programs illustrate the implementation of remove() method:

Program 1:

Java

// Java code to show the implementation of
// remove method in SortedMap interface

import java.util.*;

public class GfG {

    // Driver code
    public static void main(String[] args)
    {

        // Initializing a SortedMap
        SortedMap<Integer, String> map
            = new TreeMap<>();
        map.put(1, "One");
        map.put(3, "Three");
        map.put(5, "Five");
        map.put(7, "Seven");
        map.put(9, "Nine");
        System.out.println(map);

        map.remove(3);

        System.out.println(map);

        // If it doesn't exists, returns
        // null and does not affects the map
        map.remove(2);

        System.out.println(map);
    }
}

Output:

{1=One, 3=Three, 5=Five, 7=Seven, 9=Nine}
{1=One, 5=Five, 7=Seven, 9=Nine}
{1=One, 5=Five, 7=Seven, 9=Nine}

Program 2: Below is the code to show the implementation of remove().

Java

// Java code to show the implementation of
// remove method in SortedMap interface

import java.util.*;

public class GfG {

    // Driver code
    public static void main(String[] args)
    {

        // Initializing a SortedMap
        SortedMap<String, String> map
            = new TreeMap<>();

        map.put("1", "One");
        map.put("3", "Three");
        map.put("5", "Five");
        map.put("7", "Seven");
        map.put("9", "Nine");
        System.out.println(map);

        map.remove("3");

        System.out.println(map);
    }
}

Output:

{1=One, 3=Three, 5=Five, 7=Seven, 9=Nine}
{1=One, 5=Five, 7=Seven, 9=Nine}

Reference: https://docs.oracle.com/javase/7/docs/api/java/util/Map.html#put(K, %20V)