Working with Maps in Java

JavaMaps.java

package com.diycomputerscience;

import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;

public class JavaMaps {
  
  public static void main(String args[]) {    
    System.out.println("Creating a dictionary as a HashMap");
    Map<String, String> dictionaryAsHashMap = createDictionaryAsHashMap();
    System.out.println("Printing the HashMap");
    retrieve(dictionaryAsHashMap);
    
    System.out.println("");
    
    System.out.println("Creating a dictionary as a TreeMap");
    Map<String, String> dictionaryAsTreeMap = createDictionaryAsTreeMap();
    System.out.println("Printing the HashMap");
    retrieve(dictionaryAsTreeMap);    
  }

  private static Map<String, String> createDictionaryAsHashMap() {
    Map<String, String> dictionary = new HashMap<String, String>();
    dictionary.put("geek", "A term used for people who have relationships with their computers");
    dictionary.put("nerd", "Someone who is more interested in Calculus than Cricket");
    dictionary.put("workaholic", "A person who spends unreasonable hours playing Solitaire on his/her computer");
    dictionary.put("HelloWorld", "A strange form of greeting used to explain elementary programming principles");
    return dictionary;
  }
  
  private static Map<String, String> createDictionaryAsTreeMap() {
    Map<String, String> dictionary = new TreeMap<String, String>();
    dictionary.put("geek", "A term used for people who have relationships with their computers");
    dictionary.put("nerd", "Someone who is more interested in Calculus than Cricket");
    dictionary.put("workaholic", "A person who spends unreasonable hours playing Solitaire on his/her computer");
    dictionary.put("HelloWorld", "A strange form of greeting used to explain elementary programming principles");
    return dictionary;
  }
  
  private static void retrieve(Map<String, String> dictionary) {               
    Set<String> keySet = dictionary.keySet();
    for(String key : keySet) {
      System.out.println(key + " : " + dictionary.get(key));
    }
    
    System.out.println("");
    System.out.println("The meaning of 'geek' is '" + dictionary.get("geek") + "'");
  }
  
}