LinkedHashSet in Java

LinkedHashSet is a part of the Java Collections Framework and is an implementation of the Set interface. It combines the features of both HashSet and LinkedList. LinkedHashSet maintains a predictable iteration order, which is the order in which elements were inserted into the set. Like HashSet, it does not allow duplicate elements and provides constant-time performance for basic operations.

Declaration and Initialization

To use a LinkedHashSet in Java, you need to import the java.util.LinkedHashSet package. Here's an example of declaring and initializing a LinkedHashSet:

    
import java.util.LinkedHashSet;

public class Example {
    public static void main(String[] args) {
         LinkedHashSet<String> cities = new LinkedHashSet<>();

        // Adding elements to the LinkedHashSet
        cities.add("New York1");
        cities.add("London1");
        cities.add("Tokyo1");

        // No duplicate elements allowed
        cities.add("New York1"); // This won't be added

        // Accessing elements
        for (String city : cities) {
            System.out.println(city);
        }

        // Removing elements
        cities.remove("London1");

        // Checking if an element exists
        boolean exists = cities.contains("Tokyo1");
        System.out.println("Tokyo1 exists in the set: " + exists)
    }
}
    
  

Common LinkedHashSet Operations

Here are some commonly used operations with LinkedHashSets:

• add(element): Adds an element to the LinkedHashSet.
• remove(element): Removes an element from the LinkedHashSet.
• contains(element): Checks if the LinkedHashSet contains a specific element.
• size(): Returns the number of elements in the LinkedHashSet.
• isEmpty(): Checks if the LinkedHashSet is empty.
• clear(): Removes all elements from the LinkedHashSet.

LinkedHashSet is an excellent choice when the requirement is to maintain a unique set of elements with a predictable order of insertion. It provides efficient and predictable performance for most set operations and is widely used in various Java applications.