Java - Insert in Map
How to insert a new Item in a Map using put() method?
Let us say, we have a Map that should contain,
John, Is a Name
Java, Is a Language
Let us insert above values to the Map in the below example.
Example :
import java.util.*;
public class MyApplication {
public static void main(String[] args) {
Map x = new HashMap<>();
x.put("John", "Is a Name");
x.put("Java", "Is a Language");
System.out.println(x);
}
}
Output :
{Java=Is a Language, John=Is a Name}
So, in the above code we have created a Map,
And used the put() method to insert values to it.
x.put("John", "Is a Name");
x.put("Java", "Is a Language");
Below is the way how the values are placed in the Map as Key value pairs. Where John is the Key and Is a Name is the value.
Duplicate Keys are not allowed in Map
So, we have a Map that contains,
John, Is a Name
Java, Is a Language
Now, let us say, we want to insert a new entry,
Where John is the Key and Is an English Name is its corresponding Value.
Let us see in the below example.
Example :
import java.util.*;
public class MyApplication {
public static void main(String[] args) {
Map x = new HashMap<>();
x.put("John", "Is a Name");
x.put("Java", "Is a Language");
x.put("John", "Is an English Name");
System.out.println(x);
}
}
Output :
{Java=Is a Language, John=Is an English Name}
So, for the Key John, the initial value was Is a Name.
x.put("John", "Is a Name");
And we wanted to add a new entry with the Key as John and the Value as Is an English Name.
x.put("John", "Is an English Name");
But if we see the output.
