The java.util.HashMap.get() method of HashMap class is used to retrieve or fetch the value mapped by a particular key mentioned in the parameter. It returns NULL when the map contains no such mapping for the key.
Syntax:
Hash_Map.get(Object key_element)
Parameter: The method takes one parameter key_element of object type and refers to the key whose associated value is supposed to be fetched.
Return Value: The method returns the value associated with the key_element in the parameter.
Below programs illustrates the working of java.util.HashMap.get() method:
Program 1: Mapping String Values to Integer Keys.
// Java code to illustrate the get() methodimport java.util.*; public class Hash_Map_Demo { public static void main(String[] args) { // Creating an empty HashMap HashMap<Integer, String> hash_map = new HashMap<Integer, String>(); // Mapping string values to int keys hash_map.put(10, "Geeks"); hash_map.put(15, "4"); hash_map.put(20, "Geeks"); hash_map.put(25, "Welcomes"); hash_map.put(30, "You"); // Displaying the HashMap System.out.println("Initial Mappings are: " + hash_map); // Getting the value of 25 System.out.println("The Value is: " + hash_map.get(25)); // Getting the value of 10 System.out.println("The Value is: " + hash_map.get(10)); }} |
Output:
Initial Mappings are: {20=Geeks, 25=Welcomes, 10=Geeks, 30=You, 15=4}
The Value is: Welcomes
The Value is: Geeks
Program 2: Mapping Integer Values to String Keys.
// Java code to illustrate the get() methodimport java.util.*; public class Hash_Map_Demo { public static void main(String[] args) { // Creating an empty HashMap HashMap<String, Integer> hash_map = new HashMap<String, Integer>(); // Mapping int values to string keys hash_map.put("Geeks", 10); hash_map.put("4", 15); hash_map.put("Geeks", 20); hash_map.put("Welcomes", 25); hash_map.put("You", 30); // Displaying the HashMap System.out.println("Initial Mappings are: " + hash_map); // Getting the value of "Geeks" System.out.println("The Value is: " + hash_map.get("Geeks")); // Getting the value of "You" System.out.println("The Value is: " + hash_map.get("You")); }} |
Output:
Initial Mappings are: {4=15, Geeks=20, You=30, Welcomes=25}
The Value is: 20
The Value is: 30
Note: The same operation can be performed with any type of Mappings with variation and combination of different data types.
