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HashSet in Java with Different Examples

Hashset java expands and implements the Set interface of AbstractSet. It produces a list for storage that uses a hash table.

By using a process called hashing, a hash table stores details. The informative output of a key is used in hashing to evaluate a significant value, named its hash code.

The hash code is often used as the address at which the key relevant information is collected. The conversion of a key into its hash code is immediately worked out.

Key things to know about hashset java

The important things about the java hashset class are:

  • By using a process called hashing, Hashset preserves the items.
  • The hashset in java only includes distinct features.
  • A null value is allowed by HashSet.
  • HashSet is a non-synchronized class.
  • Hashset java doesn’t preserve the order of insertion. Here on the grounds of their hashcode, components are added.
  • For search operations, HashSet is the perfect strategy.
  • The HashSet’s nominal baseline capacity is only 16, and further, the load factor is only 0.75.

Crucial terms used in hashset java

a) Basic capacity: The initial or basic capacity in hashset java indicates the number of containers formed when hashtable (HashSet uses relatively hashtable data format). When the maximum capacity becomes complete, the total amount of buckets always expands by itself.

b) The load factor: Until its capability is automatically expanded, the load factor is a measure of how complete the HashSet is permitted to get. The hash table is then rehashed (that is, existing data objects are remodeled) when the total amount of items present in the hash table expands the amount of the load factor and the current storage, such that nearly twice the total amount of buckets are present in that hash table.

Unique hashset java methodologies

The different methodologies that are utilized in hashset java are elaborated below:

  1. boolean add(item i) – An item i is added to the list.
  2. object clone() – A copy that is shallow of the HashSet is returned by this methodology.
  3. void clear() – It removes or deletes all the items from an existing list.
  4. Int size() – Total number of items in a set or list is retrieved.
  5. boolean(item i) – It removes or deletes the particular item from a set of lists or set.
  6. boolean isEmpty() – It gives the output as True if the list or set does not have the particular item.
  7. boolean contains(item i) – It examines whether or not the item i mentioned is present in the set or list. If it is there then it gives the output True else it gives us the output False.

Example 1

Let’s have an eye on the various java hashset example which will help you to develop your skills more in the topic. Here you go!

import java.util.*;
class Demo_hash{
public static void main(String args[]){
//Let’s generate a hashset and add new items in it
HashSet<String> hst= new HashSet<String>();
hst.add(“till now!!”);
Iterator<String> itr= set.iterator();
while (itr.hasNext())

Output of the illustration will be:

# coding
# Java
# best
# is
# till now!!
# In this illustration, you can conclude that the items in hashset are iterated in an unordered manner and the same is the output that is in an unordered way.

Example 2

Below, we represent another illustration of hashset java. Let’s have an immediate look on it.

import java.util.*;
public class Demo_hash2{
public static void main(String args[]){
//Let’s declare the hashset in java
HashSet<String> hst= new HashSet<String>();
//Let’s add the items into hashset
//Let’s add some duplicate or same items into our hashset
//Let’s add some some null items or values into our hashset
//Let’s display the total items present in hashset


# [null, Python, RUBY, JAVA]
# In this illustration, the duplicate or same items in the hashset are automatically deleted or removed.


  • By using a process called hashing, HashSet saves the items.
  • The HashSet only includes unique elements.
  • A null value is permitted by HashSet.


  • HashSet is a non-synchronized group.
  • HashSet does not always retain the pattern of insertion. And depending on their hashcode, components are added.
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