Java Collection size() Method with Examples

by Online Tutorials Library July 22, 2022

Java Collection size() method

The size() method of Java Collection Interface returns the total count of the elements contained in this collection.

Syntax

Parameters

Return Value

The size() method returns the total count of the elements present in this collection.

Example 1

  import java.util.Collection;  import java.util.HashSet;  public interface JavaCollectionSizeExample1 {      public static void main(String[] args) {          Collection<Integer> collection = new HashSet<>();          //add integer values in this collection          collection.add(34);          collection.add(12);          collection.add(45);          System.out.print(“The elements in Collection : “);          System.out.println(collection);          //returns the size of the collection          System.out.println(“Size of the collection “+collection.size());      }  }  

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Output:

The elements in Collection : [34, 12, 45]  Size of the collection 3

Example 2

  import java.util.ArrayList;  import java.util.Collection;  import java.util.List;  import java.util.concurrent.ConcurrentLinkedQueue;  public class JavaCollectionSizeExample2 {      public static void main(String[] args) {          Collection<Character> collection = new ConcurrentLinkedQueue<Character>();          char i;          for(i=’a’;i<=’z’;++i){              collection.add(i);          }          //returns the total size of the collection          System.out.println(“Total alphabets : “+collection.size());          System.out.println(“collection : “+collection);          List<Character> list = new ArrayList<Character>();          list.add(‘a’);          list.add(‘e’);          list.add(‘i’);          list.add(‘o’);          list.add(‘u’);          collection.retainAll(list);          // returns the size of the collection          System.out.println(“Number of vowels : “+collection.size());          System.out.println(“Vowels : “+collection);        }  }  

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Output:

Total alphabets : 26  collection : [a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z]  Number of vowels : 5  Vowels : [a, e, i, o, u]

Example 3

  import java.util.Collection;  import java.util.concurrent.ConcurrentLinkedQueue;  public class JavaCollectionSizeExample3 {      public static void main(String[] args) {          Collection collection = new ConcurrentLinkedQueue();          //returns true if the queue is empty          if(collection.size()==0){              System.out.println(“The queue is empty.”);          }          else{              System.out.println(“Total elements are : “+collection.size());          }      }  }  

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Output:

The queue is empty.

Next TopicJava-Collection

add()addAll()clear()contains()containsAll()equals()hashcode()isempty()iterator java collection java methods java tutorial remove removeall removeif()retainall size()

Java Collection size() Method with Examples

Java Collection size() method

Syntax

Parameters

Return Value

Example 1

Example 2

Example 3

Java Array getShort() Method

Java ConcurrentHashMap remove() Method

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