How to print / iterate key and values of any map object?

Displaying key, values of any Map object - simplest way :

     We have many ways to display / iterate key, values of a map object. Here I am following advanced for loop and keySet.

Let us take a sample map object..

Map m=new HashMap();

                               m.put("1","one");

                               m.put("2","two");

                               m.put("3","three");

                               m.put("4","four");

                               m.put("5","five");

                               m.put("6","six");

// now we want to display all the keys with their respected values.

//We have a method called keySet() in Map interface. And this HashMap class implements that method.

//This method returns a Set object of  String elements ( we mentioned keys are strings in map object above).

 Set keySet=m.keySet();

//now we can iterate this Set without the help of iterator, because as per java guidelines from here. we can directly iterate set object using for-each loop with out the help of iterator object. So

 for(String key:keySet){

     System.out.println(key+":"+m.get(key)); // will print both key and value, and iterates..till last key.

 }//end for loop

// instead we can also write in a simple step using below line

for(String key:m.keySet()){

   System.out.println(key+":"+m.get(key));

}//end for loop

This is the benefit of for-each loop. Here we use for-each instead of using iterator object, and also we are no need to check for next object existence. 

code snippet:

Test.java

import java.util.*;

public class Test{

public static void main(String nag[]){

Map mp=new HashMap();

mp.put("i","one");

mp.put("2","two");

mp.put("3","three");

System.out.println("iterating....");

Set keySet=mp.keySet();

for(String key:keySet){

                       System.out.println(key+":"+mp.get(key));

}//end loop

            System.out.println("trying new one..:");

         for(String key:mp.keySet()){

                 System.out.println(key+"-"+mp.get(key));

}//end loop

System.out.println("done with new tech..");

}//end main

}//end class

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