JAVA

linkedhashmap in java

LinkedHashMap is same as HasHMap just additionally maintains the insertion order.

Implementation of LinkedHashMap Class in Java map

// Java Program to Illustrate the LinkedHashmap Class

// Importing required classes
import java.util.*;

// Main class
public class Main {

	// Main driver method
	public static void main(String[] args)
	{

		// Creating an empty LinkedHashMap
		Map<String, Integer> hashmap = new LinkedHashMap<>();

		// Inserting entries in the Map
		// using put() method
		hashmap.put("Banana", 100);
		hashmap.put("Orange", 200);
		hashmap.put("Mango", 300);
		hashmap.put("Apple", 400);

		// Iterating over Map
		for (Map.Entry<String, Integer> e : hashmap.entrySet())

			// Printing key-value pairs
			System.out.println(e.getKey() + " "+ e.getValue());
	}
}

linkedhashmap in java

LinkedHashMap can have null key, keeps order

Java Creating LinkedHashMap from Other Maps

import java.util.LinkedHashMap;

class Main {
    public static void main(String[] args) {
        // Creating a LinkedHashMap of even numbers
        LinkedHashMap<String, Integer> evenNumbers = new LinkedHashMap<>();
        evenNumbers.put("Two", 2);
        evenNumbers.put("Four", 4);
        System.out.println("LinkedHashMap1: " + evenNumbers);

        // Creating a LinkedHashMap from other LinkedHashMap
        LinkedHashMap<String, Integer> numbers = new LinkedHashMap<>(evenNumbers);
        numbers.put("Three", 3);
        System.out.println("LinkedHashMap2: " + numbers);
    }
}