HashMap get() Method in Java
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:
Now, let's discuss some programs for it:
Program 1:
Mapping String Values to Integer Keys.
// Java code to illustrate the get() method
import 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() method
import 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.
