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How to create a dictionary in Java

A java dictionary is an abstract class that stores key-value pairs. Given a key, its corresponding value can be stored and retrieved as needed; thus, a dictionary is a list of key-value pairs.

The Dictionary object classes are implemented in java.utils.

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Creating a dictionary

The first step to creating a dictionary in Java is to choose a class that implements a “key-value pair” interface; a few examples include HashTables, HashMap, and LinkedHashMap.


The declaration and initialization of a dictionary follows the syntax below:

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The code snippet below illustrates how to create a dictionary in Java and the usage of a few of the class’s methods:

import java.util.*;

class My_Dictionary 
	public static void main(String[] args)
		// creating a My HashTable Dictionary
		Hashtable<String, String> my_dict = new Hashtable<String, String>();

    // Using a few dictionary Class methods
		// using put method
		my_dict.put("01", "Apple");
		my_dict.put("10", "Banana");
		// using get() method
    System.out.println("\nValue at key = 10 : " + my_dict.get("10")); 
    System.out.println("Value at key = 11 : " + my_dict.get("11"));
		// using isEmpty() method
    System.out.println("\nIs my dictionary empty? : " + my_dict.isEmpty() + "\n");
		// using remove() method 
		// remove value at key 10
    System.out.println("Checking if the removed value exists: " + my_dict.get("10")); 
    System.out.println("\nSize of my_dict : " + my_dict.size()); 



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