Java HashMap - put() Method
The java.util.HashMap.put() method is used to associate the specified value with the specified key in the map. If the key is already present in the map, the old value is replaced.
Syntax
public V put(K key, V value)
Here, K and V are the type of key and value respectively maintained by the container.
Parameters
key |
Specify the key with which the specified value is to be associated. |
value |
Specify the value to be associated with the specified key. |
Return Value
Returns previous value associated with given key, or null if there was no mapping for key.
Exception
NA
Example:
In the example below, the java.util.HashMap.put() method is used to associate key-value pairs in the given map.
import java.util.*;
public class MyClass {
public static void main(String[] args) {
//creating a hash map
HashMap<Integer, String> MyMap = new HashMap<Integer, String>();
//populating hash map
MyMap.put(101, "John");
MyMap.put(102, "Marry");
MyMap.put(103, "Kim");
MyMap.put(104, "Jo");
//printing hash map
System.out.println("MyMap contains: " + MyMap);
//change a key-value pair
MyMap.put(103, "Ramesh");
//printing hash map
System.out.println("MyMap contains: " + MyMap);
}
}
The output of the above code will be:
MyMap contains: {101=John, 102=Marry, 103=Kim, 104=Jo}
MyMap contains: {101=John, 102=Marry, 103=Ramesh, 104=Jo}
❮ Java.util - HashMap
