JAVA EXAMPLE PROGRAMS

JAVA EXAMPLE PROGRAMS

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Program: Basic HashSet Operations.


Description:

Below example shows basic operations on HashSet object like creating object, adding elements, verifying whether the hashset is empty or not, removing an element, size of the hashset, and to check whether an object exists or not.


Code:
package com.java2novice.hashset;

import java.util.HashSet;

public class MyBasicHashSet {

	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(hs);
		System.out.println("Is HashSet empty? "+hs.isEmpty());
		hs.remove("third");
		System.out.println(hs);
		System.out.println("Size of the HashSet: "+hs.size());
		System.out.println("Does HashSet contains first element? "+hs.contains("first"));
	}
}

Output:
[second, third, first]
Is HashSet empty? false
[second, first]
Size of the HashSet: 2
Does HashSet contains first element? true
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
wait Vs sleep methods
sleep(): It is a static method on Thread class. It makes the current thread into the "Not Runnable" state for specified amount of time. During this time, the thread keeps the lock (monitors) it has acquired.

wait(): It is a method on Object class. It makes the current thread into the "Not Runnable" state. Wait is called on a object, not a thread. Before calling wait() method, the object should be synchronized, means the object should be inside synchronized block. The call to wait() releases the acquired lock.
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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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