JAVA EXAMPLE PROGRAMS

JAVA EXAMPLE PROGRAMS

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Program: How to copy all elements from HashSet to an array?


Description:

Below example shows how to copy all elements from HashSet to an array. By calling toArray() method and passing existing array object to this method, we can copy all elements of HashSet to an array.


Code:
package com.java2novice.hashset;

import java.util.HashSet;

public class MyHashSetToArray {

	public static void main(String a[]){
		HashSet<String> hs = new HashSet<String>();
		//add elements to HashSet
		hs.add("first");
		hs.add("second");
		hs.add("third");
		System.out.println("HashSet content: ");
		System.out.println(hs);
		String[] strArr = new String[hs.size()];
		hs.toArray(strArr);
		System.out.println("Copied array content:");
		for(String str:strArr){
			System.out.println(str);
		}
	}
}

Output:
HashSet content: 
[second, third, first]
Copied array content:
second
third
first
<< Previous Program | Next Program >>

List Of All HashSet Sample Programs:

  1. Basic HashSet Operations.
  2. How to iterate through HashSet?
  3. How to copy Set content to another HashSet?
  4. How to delete all elements from HashSet?
  5. How to copy all elements from HashSet to an array?
  6. How to compare two sets and retain elements which are same on both sets?
  7. How to eliminate duplicate user defined objects from HashSet?
  8. How to find user defined objects from HashSet?
  9. How to delete user defined objects from HashSet?
Knowledge Centre
Difference between Enumeration and Iterator
The functionality of Enumeration and the Iterator are same. You can get remove() from Iterator to remove an element, while while Enumeration does not have remove() method. Using Enumeration you can only traverse and fetch the objects, where as using Iterator we can also add and remove the objects. So Iterator can be useful if you want to manipulate the list and Enumeration is for read-only access.
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About Author

I'm Nataraja Gootooru, programmer by profession and passionate about technologies. All examples given here are as simple as possible to help beginners. The source code is compiled and tested in my dev environment.

If you come across any mistakes or bugs, please email me to [email protected].

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Reference: Java™ Platform Standard Ed. 7 - API Specification | Java™ Platform Standard Ed. 8 - API Specification | Java is registered trademark of Oracle.
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