Java Examples - Collection Size

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Problem Description:

How to get size of a collection?

Solution:

Following example shows how to get the size of a collection by the use of collection.add() to add new data and collection.size() to get the size of the collection of Collections class.

import java.util.*;

public class CollectionTest {
   public static void main(String [] args) {   
      System.out.println( "Collection Example!\n" ); 
      int size;
      HashSet collection = new HashSet ();
      String str1 = "Yellow", str2 = "White", str3 = 
      "Green", str4 = "Blue";  
      Iterator iterator;
      collection.add(str1);    
      collection.add(str2);   
      collection.add(str3);   
      collection.add(str4);
      System.out.print("Collection data: ");  
      iterator = collection.iterator();     
      while (iterator.hasNext()){
         System.out.print(iterator.next() + " ");  
      }
      System.out.println();
      size = collection.size();
      if (collection.isEmpty()){
         System.out.println("Collection is empty");
      }
      else{
         System.out.println( "Collection size: " + size);
      }
      System.out.println();
   }
}

Result:

The above code sample will produce the following result.

Collection Example!

Collection data: Blue White Green Yellow
Collection size: 4


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