HashSet remove() Method in Java

HashSet remove() method is used to remove a particular element from a HashSet. Note that it is only after JDK version 1.2 and ahead, and will throw compilation errors before in version JDK 1 and JDK1.1. 

Note: This method returns true if the specified element is present in the HashSet otherwise it returns boolean false.

Syntax:

HashSet.remove(Object O)

Parameters: The parameter O is of the type of HashSet and specifies the element to be removed from the HashSet.

Return Value: Boolean true and false 

Example 1:

Java

// Java code to illustrate
// HashSet.remove() method
// over String Elements

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

// Main class
// HashSet demo
public class GFG {

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

        // Creating an empty HashSet
        // Declaring object of string type
        HashSet<String> set = new HashSet<String>();

        // Adding custom input elements into the Set
        // using add() method
        set.add("Welcome");
        set.add("To");
        set.add("Geeks");
        set.add("For");
        set.add("Geeks");

        // Displaying the HashSet(object elements)
        System.out.println("HashSet: " + set);

        // Removing elements
        // using remove() method
        set.remove("Geeks");
        set.remove("For");
        set.remove("Welcome");

        // Now displaying the HashSet after removal
        // of elements from it
        System.out.println(
            "HashSet after removing elements: " + set);
    }
}

Output

HashSet: [Geeks, For, Welcome, To]
HashSet after removing elements: [To]

Example 2:

Java

// Java code to illustrate remove()
// method of Hashset class
// over Integer Elements

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

// Main class
public class GFG {

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

        // Creating an empty HashSet
        // Declaring object of integer type
        HashSet<Integer> set = new HashSet<Integer>();

        // Adding custom input elements into the Set
        // using add() method
        set.add(5);
        set.add(3);
        set.add(1);
        set.add(4);
        set.add(3);

        // Displaying the HashSet(object elements)
        System.out.println("HashSet: " + set);

        // Removing elements
        // using remove() method
        set.remove(3);
        set.remove(1);

        // Now displaying the HashSet after removal
        // of elements from it
        System.out.println(
            "HashSet after removing elements: " + set);
    }
}

Output

HashSet: [1, 3, 4, 5]
HashSet after removing elements: [4, 5]