Open In App

AbstractMap put() Method in Java with Examples

Improve
Improve
Like Article
Like
Save
Share
Report

The AbstractMap put() method inserts a mapping into an AbstractMap. This means we can add a specific key and its value, into a particular map. If an existing key is passed, then the previous value gets replaced by the new value. If a new pair is passed, then the pair gets inserted as a whole.

Example:

Java




import java.util.*;
 
public class GFG {
    public static void main(String[] args) {
 
        // Creating an empty AbstractMap
        AbstractMap<Integer, String> absMap = new HashMap<>();
 
        // Mapping string values to int keys
        absMap.put(1, "Java");
        absMap.put(2, "JavaScript");
        absMap.put(3, "Python");
 
        // Displaying the AbstractMap
        System.out.println("Initial Mappings are: " + absMap);
 
        // Inserting existing key along with new value
        String returnedValue = absMap.put(3, "Geeks");
 
        // Verifying the returned value
        System.out.println("Returned value is: " + returnedValue);
 
        // Displaying the new map
        System.out.println("New map is: " + absMap);
    }
}


Output:

Initial Mappings are: {1=Java, 2=JavaScript, 3=Python}
Returned value is: Python
New map is: {1=Java, 2=JavaScript, 3=Geeks}

Syntax

AbstractMap.put(key, value)

Parameters

  • key: This refers to the key element that needs to be inserted into the Map for mapping.
  • value: This refers to the value that the above key would map into.

Returns

  • If an existing key is passed then the previous value gets returned. 
  • If a new pair is passed, then NULL is returned. 

Exceptions

  • NullPointerException– When the specified key is null.

AbstractMap put() Method Examples

Let’s see some examples of how to use the Java AbstractMap put() method in Java.

Example 1:

How to add a new element in AbstractMap with Java put() function (passing an existing key).

Java




import java.util.*;
 
public class AbstractMapDemo {
    public static void main(String[] args) {
 
        // Creating an empty AbstractMap
        AbstractMap<Integer, String> absMap = new HashMap<>();
 
        // Mapping string values to int keys
        absMap.put(10, "Geeks");
        absMap.put(15, "4");
        absMap.put(20, "Geeks");
        absMap.put(25, "Welcomes");
        absMap.put(30, "You");
 
        // Displaying the AbstractMap
        System.out.println("Initial Mappings are: " + absMap);
 
        // Inserting existing key along with new value
        String returnedValue = absMap.put(20, "All");
 
        // Verifying the returned value
        System.out.println("Returned value is: " + returnedValue);
 
        // Displaying the new map
        System.out.println("New map is: " + absMap);
    }
}


Output

Initial Mappings are: {20=Geeks, 25=Welcomes, 10=Geeks, 30=You, 15=4}
Returned value is: Geeks
New map is: {20=All, 25=Welcomes, 10=Geeks, 30=You, 15=4}

Example 2:

Adding a new element in AbstractMap (passing a new key).

Java




import java.util.*;
 
public class AbstractMapDemo {
    public static void main(String[] args) {
 
        // Creating an empty AbstractMap
        AbstractMap<Integer, String> absMap = new HashMap<>();
 
        // Mapping string values to int keys
        absMap.put(10, "Geeks");
        absMap.put(15, "4");
        absMap.put(20, "Geeks");
        absMap.put(25, "Welcomes");
        absMap.put(30, "You");
 
        // Displaying the AbstractMap
        System.out.println("Initial Mappings are: " + absMap);
 
        // Inserting a new key-value pair
        String returnedValue = absMap.put(50, "All");
 
        // Verifying the returned value
        System.out.println("Returned value is: " + returnedValue);
 
        // Displaying the new map
        System.out.println("New map is: " + absMap);
    }
}


Output

Initial Mappings are: {20=Geeks, 25=Welcomes, 10=Geeks, 30=You, 15=4}
Returned value is: null
New map is: {50=All, 20=Geeks, 25=Welcomes, 10=Geeks, 30=You, 15=4}

Note: The same operation can be performed with any type of Mappings with variation and combination of different data types.

Read More AbstractMap Methods

Whether you are a beginner starting Java programming or an experienced looking to brush up on your Java skills, this tutorial will provide you with a deep understanding of the AbstractMap put function and its uses in Java.

The AbstractMap put() method in Java is a fundamental function for AbstractMap manipulation. With this guide, you can easily add/put new elements to AbstractMap using the AbstractMap put function.



Last Updated : 16 Feb, 2024
Like Article
Save Article
Previous
Next
Share your thoughts in the comments
Similar Reads