Java Tutorial

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Java Loops

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Java Programs

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Java Sorting

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Java OOPs Concepts

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Java Strings

Java Strings Java String Methods StringBuilder in Java StringBuffer in Java Java Regular Expressions StringBuffer vs StringBuilder String vs StringBuffer String vs StringBuilder String Manipulation in Java Java String Concatenation How to Reverse a String in Java String Array in Java How to Compare Two Strings in Java How to Concatenate Two Strings in Java Why String in Immutable in Java java.lang.NumberFormatException for Input String String Pool in Java Java Generate Random String How to take String Input in Java Java String Interview Questions

Java Exceptions

Exception Handling in Java Java try catch Java throw Java throws Difference between throw and throws Java finally Java Custom Exception Java Exception Propagation

Garbage Collection

Automatic Resource Management in Java Java Garbage Collection Java finalize() Java gc() Difference between final, finally and finalize

Multithreading

Multithreading in Java Process and Thread in Java Basic Terms in Multithreading Java Thread creation Thread Scheduler in Java Java Thread class DeadLock in Java

Java IO

Java IO Java Read File Java BufferedWriter Java InputStreamReader Java File Java Read File Line By Line Java FileOutputStream Jar File in Java

Serialization

Java Serialization Java transient

Networking

Java Network Programming Java Socket Programming Java URL Java URLConnection HttpURLConnection in Java Java InetAddress Java DatagramSocket and Java DatagramPacket

AWT

Java AWT

Swing

Swing in Java

Java Collections

Collections in Java Java List Interface ArrayList in Java LinkedList in Java Vector in Java Stack in Java ArrayList vs LinkedList in Java ArrayList vs Vector in Java Java Set Interface HashSet in Java LinkedHashSet in Java TreeSet in Java Java Queue Interface PriorityQueue in Java ArrayDeque in Java Java Map Interface HashMap in Java LinkedHashMap in Java TreeMap in Java Dictionary in Java Hashtable in Java Properties in Java Collections class in Java Java Comparable Java Comparator Comparable vs Comparator in Java

Java Generics

Generics in Java

Java Annotations

Annotations in Java

Java JDBC

Java JDBC Tutorial

Java Differences

Java vs JavaScript Python vs Java Kotlin vs Java Java vs C++ C# vs Java Static vs Non-static in Java C vs Java int vs Integer in Java Stack vs Heap in Java Java Array vs ArrayList

How to

How to run Java program How to set path in Java How to check the Java version in cmd How to install Java in Windows 10 How to run Java program in cmd How to call a method in Java How to sort an array in Java How to iterate HashMap in Java How to write Java program How to create an array in Java How to create a package in Java How to generate random numbers in Java How to input String in Java How to create thread in Java How to find length of String in Java How to sort a string in Java How to use scanner in Java How to achieve multiple inheritance in Java How to run Java program in Eclipse How to call a function in Java How to create array of objects in Java How to create custom exception in Java How to achieve abstraction in Java How to call static method in Java

Java 8 Features

Java 8 Features Lambda Expressions in Java Functional Interface in Java Streams in Java Java Base64 Encoding and Decoding Parallel Arrays Sort in Java

Java 9 Features

Java 9 Tutorial Java 9 Try With Resources Java 9 Interface Private Method

Java Servlet Tutorial

Java Servlets Tutorial

Java JSP Tutorial

Java JSP Tutorial

Hibernate Tutorial

Hibernate Tutorial

Spring Tutorial

Spring Tutorial

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Spring MVC Tutorial

Jenkins Tutorial

Jenkins Tutorial

Java Math Methods

Math.abs() Math.acos() Math.addExact() Math.asin() Math.atan () Math.atan2() Math.cbrt() Math.ceil() Math.copysign() Math.cos() Math.cosh() Math.decrementExact() Math.exp() Math.expm1() Math.floor() Math.floorDiv() Math.floorMod() Math.getExponent() Math.hypot() Math.IEEEremainder() Math.incrementExact() Math.log() Math.log10() Math.log1p() Math.max() Math.min() Math.multiplyExact() Math.multiplyFull() Math.negateExact() Math.nextAfter() Math.nextDown() Math.nextUp() Math.pow() Math.random() Math.rint() Math.round() Math.scalb() Math.signum() Math.sin() Math.sinh() Math.sqrt() Math.subtractExact() Math.tan() Math.tanh() Math.toDegrees() Math.toIntExact() Math.toRadians() Math.ulp()

Java String Methods

toCharArray() copyValueOf() endsWith() equals() equalsIgnoreCase() format() getBytes() getChars() hashCode() indexOf() intern() isEmpty() join() lastIndexOf() length() replace() replaceAll() replaceFirst() split() startsWith() subSequence() substring() toLowerCase() toUpperCase() trim() valueOf()

Java Conversion

Java Convert String to int Java Convert int to String Java Convert String to long Java Convert long to String Java Convert String to float Java Convert float to String Java Convert String to double Java Convert double to String Java Convert String to Date Java Convert Date to String Java Convert String to Object Java Convert Object to String Java Convert String to char Java Convert char to String Java Convert int to long Java Convert long to int

Misc

Functional Interfaces in Java Singleton class in Java Awesome explanation of Strings in Java Object class in Java Static class in Java All the important string methods in Java String Handling Method in Java What are Array strings in Java Advantages and Disadvantages of Strings in Java Big Decimal class in Java Class definition in Java Char and String differences in Java Difference between String, StringBuffer and StringBuilder in java Replace character in string Java String Coding Interview Questions in Java What is String in Java? String isnullorempty in Java String Matches in Java Trim Method in String Java Bean class in Java Libraries in Java Arithmetic Operations on String in Java Convert Char array to string in java Check whether Java is installed or not How to calculate time difference in Java How to stop execution after a certain time in Java Jagged Array in Java Java ArraylistRemove() Time Complexity Java Swing Time Picker Zigzag Array in Java

Java LinkedHashSet

LinkedHashSet in Java with Example

Java LinkedHashSet extends HashSet and Implements the Set interface. It doesn’t contain only duplicate values like HashSet. It also permits the null elements. It maintains the order of insertion. It returns the elements in the order in which they are inserted. It also maintains the linked list of the elements in the set. The syntax of the LinkedHashSet is:
LinkedHashSet<String> hs= new LinkedHashSet<String> ();
It also has two factors which affect the performance of LinkedHashSet-> Load Factor and Initial Capacity. Difference between HashSet and LinkedHashSet:

Categories

HashSet

LinkedHashSet

Internal Working Internally uses HashMap for storing objects. Internally uses LinkedHashMap for storing objects.
Order Not maintain the insertion order. Maintain the insertion order.
Complexity The complexity is O(1). The complexity is O(1).
Performance Its performance is better than LinkedHashSet. Its performance is slower than HashSet due to the insertion order.
Compare It uses equals () and hashCode (). It also uses equals () and hashCode () for comparing.
Null Elements It allows only one null element. It allows only one null element.
When to use If you want unique elements but don’t want to maintain the order of insertion. It used when to want to maintain the insertion order of the elements.
Syntax HashSet<String> hs= new HashSet<String> (); LinkedHashSet<String> h= new LinkedHashSet<String> ();
 Similarities between HashSet and LinkedHashSet:
  1. The HashSet and LinkedHashSet implements Set interface. Hence, they are not allowed to keep the duplicate value.
  2. HashSet and LinkedHashSet both are cloneable and Serializable.
  3. You have to make it externally synchronize if you want to use multi-threading environment because both do not thread safe.

Time Complexity of LinkedHashSet

LinkedHashSet uses the HashTable Data Structure. The Complexity of the LinkedHashSet is O(1) time for adding, removing, and retrieving operations.

Constructors of LinkedHashSet

  1. LinkedHashSet (): It is used to create the default HashSet.
  2. LinkedHashSet (Collection c): It is used to initialize with elements of the collection.
  3. LinkedHashSet (int size): It is used to initialize the size of LinkedHashSet.
  4. LinkedHashSet (Int Capacity, float Loadfactor): This is used to initialize both the capacity and load factor.
Methods of LinkedHashSet
  1. add (object o): This method is used to add the elements in HashSet.
Example:
import java.util. LinkedHashSet;
public class AddExample {
public static void main (String args []) {
LinkedHashSet<Integer> lh= new LinkedHashSet<Integer> ();
lh.add (99);
lh.add (7);
lh.add (0);
lh.add (67);
lh.add (66);
System.out.println (lh);
}
}
Output:
[99, 7, 0, 67, 66]
  1. remove (object o): Used to remove the elements from the set.
Example:
import java.util. LinkedHashSet;
public class RemoveExample {
public static void main (String args []) {
LinkedHashSet<Integer> lh= new LinkedHashSet<Integer> ();
lh.add (99);
lh.add (7);
lh.add (0);
lh.add (67);
lh.add (66);
System.out.println (lh);
lh.remove (0);
System.out.println ("After removing: "+ lh);
}
}
Output:
[99, 7, 0, 67, 66]
After removing:
[99, 7, 67, 66]
  1. contains (object o): It returns true if the element found in the set.
Example:
import java.util. LinkedHashSet;
public class ContainExample {
public static void main (String args []) {
LinkedHashSet<Integer> lh= new LinkedHashSet<Integer> ();
lh.add (99);
lh.add (7);
lh.add (0);
lh.add (67);
lh.add (66);
System.out.println (lh);
System.out.println ("Does the set contain 67?"+ lh.contains (67));
System.out.println ("Does the set contain 99?”+ lh.contains (99));
System.out.println ("Does the set contain 88?”+ lh.contains (88));
}
}
Output:
[99, 7, 0, 67, 66]
Does the set contain 67? true Does the set contain 99? true Does the set contain 88? false
  1. isEmpty (): It returns true if the set is empty otherwise false.
Example:
import java.util. LinkedHashSet;
public class EmptyExample {
public static void main (String args []) {
LinkedHashSet<Integer> lh= new LinkedHashSet<Integer> ();
lh.add (99);
lh.add (7);
lh.add (0);
lh.add (67);
lh.add (66);
System.out.println (lh);
System.out.println ("Is the set empty: " + lh.isEmpty ());
lh.clear ();
System.out.println ("Is the set empty: " + lh.isEmpty ());
}
}
Output:
[99, 7, 0, 67, 66]
Is the set empty: false Is the set empty: true
  1. int size (): This method is used to return the number of elements in the set.
Example:
import java.util. LinkedHashSet;
public class SizeExample {
public static void main (String args []) {
LinkedHashSet<Integer> lh= new LinkedHashSet<Integer> ();
lh.add (99);
lh.add (7);
lh.add (0);
lh.add (67);
lh.add (66);
System.out.println (lh);
System.out.println ("The size of the element: "+lh.size ());
lh.clear ();
System.out.println ("Set contain: " + lh.size () +" elements");
}
}
Output:
[99, 7, 0, 67, 66]
The size of the element: 5 Set contain: 0 elements
  1. retainAll (): It is used to retain the entire element from the collection and show only those elements that are same in both Sets.
Example:
import java.util. LinkedHashSet;
public class RetainAllExample {
public static void main (String args []) {
LinkedHashSet<Integer> lh= new LinkedHashSet<Integer> ();
lh.add (99);
lh.add (7);
lh.add (0);
lh.add (67);
lh.add (66);
System.out.println ("The element before retainAll operation: "+ lh);
LinkedHashSet<Integer> lh2= new LinkedHashSet<Integer> ();
lh2.add (100);
lh2.add (78);
lh2.add (67);
lh2.add (17);
lh2.add (66);
System.out.println ("The element for retain: "+lh2);
lh.retainAll (lh2);
System.out.println ("The elements after retainAll operation: "+lh);
}
}
Output: The element before retainAll operation:
[99, 7, 0, 67, 66]
The element for retain:
[100, 78, 67, 17, 66]
The elements after retainAll operation:
[67, 66]
  1. hashCode (): It is used to get the hashcode value of the instance of the LinkedHashSet.
Example:
import java.util. LinkedHashSet;
public class HashCodeExample {
public static void main (String args []) {
LinkedHashSet<Integer> lh= new LinkedHashSet<Integer> ();
lh.add (99);
lh.add (7);
lh.add (0);
lh.add (67);
lh.add (66);
System.out.println ("The element: "+ lh);
System.out.println ("The hashcode value: "+lh.hashCode ());
}
}
Output: The element:
[99, 7, 0, 67, 66]
The hashcode value:
239

Difference between LinkedHashSet and LinkedHashMap:

LinkedHashSet

LinkedHashMap

1. It is used to store the collection of elements. 1. It is used to store the key-value pairs.
2. It implements HashSet. 2. It Implements HashMap.
3. It doesn’t store duplicates values. 3. It stores unique keys but can store duplicate values.
4. The syntax and to add the elements in the Set is: LinkedHashSet<String> lhs= new LinkedHashSet<String> (); lhs.add(“Welcome”); lhs.add(“to”); lhs.add(“TutorialAndExample”); 4.The syntax and the add the elements in the map is: LinkedHashMap<String> lhm= new LinkedHashMap<String> (); lhm.put (“Welcome”,5); lhm.put (“to”,6); lhm.put(“TutorialAndExample”,12);

 Example using iterator() method

import java.util.*;
public class SizeExample {
public static void main (String args []) {
LinkedHashSet<Integer> lh= new LinkedHashSet<Integer> ();
lh.add (99);
lh.add (7);
lh.add (0);
lh.add (67);
lh.add (66);
System.out.println ("The element: "+ lh);
Iterator<Integer> i=lh.iterator (); 
while (i.hasNext ()) 
 { 
 System.out.println (i.next ()); 
 } 
}
}
Output: The element:
[99, 7, 0, 67, 66]
99
7
0
67
66



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