The HashSet.remove() method is present in the HashSet class inside the java.util package. The HashSet.remove() method is used to remove only the specified element from the HashSet.
Let’s understand with the help of an example.
Suppose that the Hashset contains the following: [1, 8, 5, 3, 0]. We execute the below statements on this hashset:
Hashset1.remove(8);Hashset1.remove(0);After using the remove() method, the HashSet contains [1, 5, 3].
public boolean remove(Object obj)
The HashSet.remove() accepts one parameter:
obj: The Object of HashSet type that needs to be removed from the HashSet.The HashSet.remove() method returns true if the HashSet gets changed as a result of the call to the method.
Let’s have a look at the code now.
import java.io.*;import java.util.HashSet;class Main{public static void main(String args[]){HashSet<Integer> hash_set1 = new HashSet<Integer>();hash_set1.add(1);hash_set1.add(8);hash_set1.add(5);hash_set1.add(3);hash_set1.add(0);System.out.println("hash_set1 before calling remove(): "+ hash_set1);boolean removeVal1;boolean removeVal2;removeVal1 = hash_set1.remove(150);removeVal2 = hash_set1.remove(8);System.out.println("hash_set1 after calling remove(): "+ hash_set1);System.out.println("the removal of 8 was: " + removeVal2);System.out.println("the removal of 150 was: " + removeVal1);}}
HashSet of integer type, i.e., hash_set1.HashSet by using the HashSet.add() method.HashSet before calling the remove() method.remove() function to remove specific elements from the HashSet and assign the returned values to boolean variables.150 is passed as the argument, nothing happens, as it is not present. But when 8 is removed, the change is reflected.HashSet after calling the remove() method.remove() method are displayed.