LinkedHashMap class extends HashMap and maintains a linked list of the entries in the map, in the order in which they were inserted. This allows insertion-order iteration over the map. That is, when iterating a LinkedHashMap, the elements will be returned in the order in which they were inserted.
There are basically two ways to iterate over LinkedHashMap:
- Using keySet() and get() Method
- Using entrySet() and Iterator
Method 1: Iterating LinkedHashMap using keySet() and get() Method
Syntax:
linked_hash_map.keySet()
Parameters: The method does not take any parameter.
Return Value: The method returns a set having the keys of the LinkedHashMap.
- Through keySet() method we will obtain a set having keys of the map.
- And then after running a loop over this set, we can obtain each key and its value using get() method.
Java
// Java Program to iterate through LinkedHashMap using// keySet() and get() MethodÂ
import java.util.LinkedHashMap;import java.util.Set;Â
public class GFG {Â
    public static void main(String a[])    {        // making the object of LinkedHashMap        LinkedHashMap<String, String> linkedHashMap                 = new LinkedHashMap<String, String>();               // adding the elements in linkedHashMap        linkedHashMap.put("One", "First element");        linkedHashMap.put("Two", "Second element");        linkedHashMap.put("Three", "Third element");Â
        Set<String> keys = linkedHashMap.keySet();               // printing the elements of LinkedHashMap        for (String key : keys) {            System.out.println(key + " -- "                               + linkedHashMap.get(key));        }           }} |
One -- First element Two -- Second element Three -- Third element
Method 2: Iterating LinkedHashMap using entrySet() and Iterator
Syntax:
Linkedhash_map.entrySet()
Parameters: The method does not take any parameter.
Return Value: The method returns a set having same elements as the LinkedHashMap.
Java
// Java Program to iterate over linkedHashMap using// entrySet() and iteratorÂ
import java.util.Iterator;import java.util.LinkedHashMap;import java.util.Set;Â
public class GFG {Â
    public static void main(String[] args)    {Â
        // Create a LinkedHashMap and populate it with        // elements        LinkedHashMap<String, String> linkedHashMap            = new LinkedHashMap<String, String>();Â
        // adding the elements to the linkedHashMap        linkedHashMap.put("One", "First element");        linkedHashMap.put("Two", "Second element");        linkedHashMap.put("Three", "Third element");Â
        // Get a set of all the entries (key - value pairs)        // contained in the LinkedHashMap        Set entrySet = linkedHashMap.entrySet();Â
        // Obtain an Iterator for the entries Set        Iterator it = entrySet.iterator();Â
        // Iterate through LinkedHashMap entries        System.out.println("LinkedHashMap entries : ");Â
        while (it.hasNext())            // iterating over each element using it.next()            // method            System.out.println(it.next());    }} |
LinkedHashMap entries : One=First element Two=Second element Three=Third element
