EnumMap put() Method Examples
Let’s see some examples of how to use EnumMap put() Method in Java
Example 1
How to put/add new value for the specified key in EnumMap:
Java
import java.util.*; // An enum of w3wiki enum GFG { Global_today, India_today, China } class EnumDemo { public static void main(String[] args) { EnumMap<GFG, Integer> mp = new EnumMap<>(GFG. class ); // Values are associated mp.put(GFG.Global_today, 799 ); mp.put(GFG.India_today, 69 ); // Display the initial map System.out.println( "The map is: " + mp); // Stores the old value associated with the key Integer prevValue = mp.put(GFG.India_today, 72 ); // Prints the old value System.out.println( "Previous value: " + prevValue); // Display the final map System.out.println( "The final map is: " + mp); } } |
The map is: {Global_today=799, India_today=69} Previous value: 69 The final map is: {Global_today=799, India_today=72}
Example 2
To show the working of the keyset() method in Java
Java
// Java program to demonstrate the working of keySet() import java.util.*; // an enum of w3wiki // ranking globally and in india public enum gfg { Global_today, India_today, China_today } ; class Enum_demo { public static void main(String[] args) { EnumMap<gfg, Integer> mp = new EnumMap<gfg, Integer>(gfg. class ); // Values are associated mp.put(gfg.Global_today, 799 ); mp.put(gfg.India_today, 69 ); // Display the initial map System.out.println("The map is: " + mp); // Stores the old value associated with the key int prev_value = mp.put(gfg.Global_today, 800 ); // Prints the old value System.out.println("Previous value: " + prev_value); // Display the final map System.out.println("The final map is: " + mp); } } |
The map is: {Global_today=799, India_today=69} Previous value: 799 The final map is: {Global_today=800, India_today=69}
Example 3
NullPointerException in EnumMap put() Method
Java
import java.util.*; // An enum of w3wiki enum GFG { Global_today, India_today, China } class EnumDemo { public static void main(String[] args) { EnumMap<GFG, Integer> mp = new EnumMap<>(GFG. class ); // Values are associated mp.put(GFG.Global_today, 799 ); mp.put( null , 69 ); // Display the initial map System.out.println( "The map is: " + mp); // Stores the old value associated with the key Integer prevValue = mp.put(GFG.India_today, 72 ); // Prints the old value System.out.println( "Previous value: " + prevValue); // Display the final map System.out.println( "The final map is: " + mp); } } |
Output:
Exception in thread "main" java.lang.NullPointerException
at java.base/java.util.EnumMap.typeCheck(EnumMap.java:743)
at java.base/java.util.EnumMap.put(EnumMap.java:264)
at EnumDemo.main(EnumDemo.java:16)
Read More EnumMap 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 put function and its uses in Java.
The put method in Java is a fundamental function for EnumMap manipulation. With this guide, you can easily put/add a new element to an EnumMap using the put method.
EnumMap put() Method in Java with Examples
The Java.util.EnumMap.put() method in Java associates specified key-value pairs.
In simple words, the put() method is used to add or modify entries in the EnumMap. If the values are repeated, the older values are replaced.
Example
Java
// Java Program to demonstrate the usage of EnumMap import java.util.EnumMap; // Enumeration representing programming languages enum ProgLang { Java, JavaScript, Python } // Driver Class public class Main { // Main Function public static void main(String[] args) { // Create an EnumMap to store language-program pairs EnumMap<ProgLang, String> PLM = new EnumMap<>(ProgLang. class ); // Add entries to the EnumMap PLM.put(ProgLang.Java, "Study at w3wiki" ); PLM.put(ProgLang.JavaScript, "Learn at w3wiki" ); PLM.put(ProgLang.Python, "Practice at w3wiki" ); // Overwrite an entry for Java PLM.put(ProgLang.Java, "Studying at w3wiki" ); // Print the EnumMap System.out.println(PLM); } } |
Output:
{Java=Studying at w3wiki, JavaScript=Learn at w3wiki, Python=Practice at w3wiki}