ConcurrentSkipListMap remove() method in Java with Examples

The remove() method of java.util.concurrent.ConcurrentSkipListMap is an in-built function in Java which removes the mapping for the specified key from this map. The method returns null if there is no mapping for of that particular key. After this method is performed the size of the map is reduced.

Syntax:

ConcurrentSkipListMap.remove(Object ob)

Parameter: The function accepts a single mandatory parameter ob which specifies the key whose mapping is to be removed.

Return Value: The function returns the previous value associated with the specified key, or null if there was no mapping for the key.

Below programs illustrate the above method:

// Java Program Demonstrate remove()
// method of ConcurrentSkipListMap

import java.util.concurrent.*;

class GFG {
    public static void main(String[] args)
    {

        // Initializing the map
        ConcurrentSkipListMap<Integer, Integer>
            mpp = new ConcurrentSkipListMap<Integer,
                                            Integer>();

        // Adding elements to this map
        for (int i = 1; i <= 5; i++)
            mpp.put(i, i);
        // remove() operation on the map
        mpp.remove(1);

        System.out.println("After remove(): " + mpp);
    }
}

Output:

After remove(): {2=2, 3=3, 4=4, 5=5}

Program 2:

// Java Program Demonstrate remove()
// method of ConcurrentSkipListMap

import java.util.concurrent.*;

class GFG {
    public static void main(String[] args)
    {

        // Initializing the map
        ConcurrentSkipListMap<Integer, Integer>
            mpp = new ConcurrentSkipListMap<Integer,
                                            Integer>();

        // Adding elements to this map
        for (int i = 1; i <= 5; i++)
            mpp.put(i, i);
        // remove() operation on the map
        mpp.remove(5);

        System.out.println("After remove(): " + mpp);
    }
}

Output:

After remove(): {1=1, 2=2, 3=3, 4=4}

Reference: https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/ConcurrentSkipListMap.html#remove-java.lang.Object-