Java HashSet clone() Method

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Description

The Java HashSet clone() method is used to return a shallow copy of this HashSet instance.

Declaration

Following is the declaration for java.util.HashSet.clone() method.

public Object clone()

Parameters

NA

Return Value

The method call returns a shallow copy of this set.

Exception

NA

Cloning a HashSet of Integers Example

The following example shows the usage of Java HashSet clone() method to create a shallow copy of the HashSet. We've created two HashSet objects of Integers. Then few entries are added using add() method one set and then set is printed. Now set is cloned using clone() method and printed.

package com.tutorialspoint;

import java.util.HashSet;

public class HashSetDemo {
   public static void main(String args[]) {
      
      // create hash set
      HashSet <Integer> newset = new HashSet <>();
      HashSet <Integer> newset1 = new HashSet <>();      

      // populate hash set
      newset.add(1); 
      newset.add(2);
      newset.add(3);  

      // checking elements in hash set
      System.out.println("Hash set values: "+ newset);

      // clone the set
      newset1 = (HashSet<Integer>) newset.clone();

      // print the set
      System.out.println("Cloned Hash set values: "+ newset1);
   }    
}

Output

Let us compile and run the above program, this will produce the following result.

Hash set values: [1, 2, 3]
Cloned Hash set values: [1, 2, 3]

Cloning a HashSet of Strings Example

The following example shows the usage of Java HashSet clone() method to create a shallow copy of the HashSet. We've created two HashSet objects of Strings. Then few entries are added using add() method one set and then set is printed. Now set is cloned using clone() method and printed.

package com.tutorialspoint;

import java.util.HashSet;

public class HashSetDemo {
   public static void main(String args[]) {
      
      // create hash set
      HashSet <String> newset = new HashSet <>();
      HashSet <String> newset1 = new HashSet <>();	  

      // populate hash set
      newset.add("Learning"); 
      newset.add("Easy");
      newset.add("Simply");  

      // checking elements in hash set
      System.out.println("Hash set values: "+ newset);

      // clone the set
      newset1 = (HashSet<String>) newset.clone();

      // print the set
      System.out.println("Cloned Hash set values: "+ newset1);
   }    
}

Output

Let us compile and run the above program, this will produce the following result.

Hash set values: [Learning, Easy, Simply]
Cloned Hash set values: [Learning, Easy, Simply]

Cloning a HashSet of Objects Example

The following example shows the usage of Java HashSet clone() method to create a shallow copy of the HashSet. We've created two HashSet objects of Student objects. Then few entries are added using add() method one set and then set is printed. Now set is cloned using clone() method and printed.

package com.tutorialspoint;

import java.util.HashSet;

public class HashSetDemo {
   public static void main(String args[]) {
      
      // create hash set
      HashSet <Student> newset = new HashSet <>();
      HashSet <Student> newset1 = new HashSet <>();   

      // populate hash set
      newset.add(new Student(1, "Julie")); 
      newset.add(new Student(2, "Robert"));
      newset.add(new Student(3, "Adam"));	  

      // checking elements in hash set
      System.out.println("Hash set values: "+ newset);

      // clone the set
      newset1 = (HashSet<Student>) newset.clone();

      // print the set
      System.out.println("Cloned Hash set values: "+ newset1);
   }    
}
class Student {
   int rollNo;
   String name;

   Student(int rollNo, String name){
      this.rollNo = rollNo;
      this.name = name;
   }

   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]";
   }
}

Output

Let us compile and run the above program, this will produce the following result.

Hash set values: [[ 1, Julie ], [ 2, Robert ], [ 3, Adam ]]
Cloned Hash set values: [[ 2, Robert ], [ 1, Julie ], [ 3, Adam ]]