The
LinkedHashSetis similar to theHashSet, except thatLinkedHashSetmaintains the insertion order of elements, whereasHashSetdoes not. Read more aboutLinkedHashSethere.
The add method adds an element to the LinkedHashSet object if the element is not already present.
public boolean add(E e)
This method takes the element to be added to the set as an argument.
The add method returns true if the passed element is not already present in the set. Otherwise, the method returns false.
import java.util.LinkedHashSet;class Add {public static void main( String args[] ) {LinkedHashSet<Integer> set = new LinkedHashSet<>();set.add(1);set.add(2);set.add(3);System.out.println("Calling set.add(3). Is added - " + set.add(3));System.out.println("Calling set.add(4). Is added - " + set.add(4));System.out.println("The set is " + set);}}
In the code above, we:
In line 1: Import the LinkedHashSet class.
In line 4: Create a new LinkedHashSet object with the name set.
From lines 5 to 7: Use the add method to add three elements (1,2,3) to the set object.
In line 10: Use the add method to add element 3 to the set. The element 3 is already present in the set, so the set remains unchanged and the method returns false.
In line 11: Use the add method to add element 4 to the set. The element 4 is not present in the set, so the element is added to the set and the method returns true.