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Java lessons (39/47)

Java — HashSet

Create HashSet

import java.util.HashSet;

HashSet<String> set = new HashSet<>();

Add elements

set.add("Alice");
set.add("Bob");
set.add("Alice");  // Duplicate ignored

Check existence

boolean hasAlice = set.contains("Alice");

Remove elements

set.remove("Bob");

Size

int count = set.size();

Mini Practice

  1. Create HashSet
  2. Add elements
  3. Check duplicates
  4. Practice set operations

Up Next

Continue with Iterator - Collection traversal.

Related Topics

HashMapIteratorExceptionsRegEx

Frequently Asked Questions about HashSet

What is HashSet in Java?

HashSet is a fundamental concept in Java. This lesson explains it step by step with clear examples, making it easy for beginners to understand.

How do I learn HashSet?

Start by reading the explanation above, then try the code examples. Practice by modifying the examples and experimenting with different values. Hands-on practice is the best way to learn HashSet.

Why is HashSet important in Java?

HashSet is essential for Java development. Understanding this concept will help you write better code and solve real-world problems more effectively.