Java Dictionary size() Method

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Description

The Java Dictionary size() method returns the number of entries (distinct keys) in this dictionary.

Declaration

Following is the declaration for java.util.Dictionary.size() method

public abstract int size()

Parameters

NA

Return Value

This method returns the number of keys in this dictionary.

Exception

NA

Getting Size of Dictionary of Integer,Integer Pair Example

The following example shows the usage of Java Dictionary size() method. We're creating a dictionary instance using Hashtable object of Integer, Integer. We're checking status of dictionary using size() method and printing the result. Then we've added few elements to it and status of dictionary using size() method and print the result.

package com.tutorialspoint;

import java.util.Dictionary;
import java.util.Hashtable;

public class DictionaryDemo {
   public static void main(String[] args) {

      // create a new hashtable
      Dictionary<Integer, Integer> dictionary = new Hashtable<>();
      System.out.println(dictionary.size());

      // add 2 elements
      dictionary.put(1, 1);
      dictionary.put(2, 2);

      System.out.println(dictionary.size());
   }
}

Output

Let us compile and run the above program, this will produce the following result −

0
2

Getting Size of Dictionary of Integer,String Pair Example

The following example shows the usage of Java Dictionary size() method. We're creating a dictionary instance using Hashtable object of Integer, String pairs. We're checking status of dictionary using size() method and printing the result. Then we've added few elements to it and status of dictionary using size() method and print the result.

package com.tutorialspoint;

import java.util.Dictionary;
import java.util.Hashtable;

public class DictionaryDemo {
   public static void main(String[] args) {

      // create a new hashtable
      Dictionary<Integer, String> dictionary = new Hashtable<>();
      System.out.println(dictionary.size());

      // add 2 elements
      dictionary.put(1, "One");
      dictionary.put(2, "Two");
      System.out.println(dictionary.size());
   }
}

Output

Let us compile and run the above program, this will produce the following result −

0
2

Getting Size of Dictionary of Integer,Object Pair Example

The following example shows the usage of Java Dictionary size() method. We're creating a dictionary instance using Hashtable object of Integer, Student pairs. We're checking status of dictionary using size() method and printing the result. Then we've added few elements to it and status of dictionary using size() method and print the result.

package com.tutorialspoint;

import java.util.Dictionary;
import java.util.Hashtable;

public class DictionaryDemo {
   public static void main(String[] args) {

      // create a new hashtable
      Dictionary<Integer, Student> dictionary = new Hashtable<>();
      System.out.println(dictionary.size());

      // add 2 elements
      dictionary.put(1, new Student(1, "Julie"));
      dictionary.put(2, new Student(2, "Robert"));

      System.out.println(dictionary.size());
   }
}
class Student {
   int rollNo;
   String name;

   Student(int rollNo, String name){
      this.rollNo = rollNo;
      this.name = name;
   }

   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]";
   }
}

Output

Let us compile and run the above program, this will produce the following result −

0
2