Code in java show proper comments on each line of code This assignment will help

Question

Code in java show proper comments on each line of code

This assignment will help you to master the following concepts: HashMap Comparator 3. Prerequisites Not applicable. 4. Associated Data Files Not applicable. 5. Problem Statement Create a HashMap object in the Java Program and perform the following functionalities Add key value pairs to the HashMap object Add a key-value pair to the HashMap object if the key-value pair doesn't exist already. Retrieve a value associated with a given key from the HashMap. Clear all the key-value pair present in the HashMap.

Explanation / Answer

HashMapDemo.java

import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

public class HashMapDemo {

public static void main(String[] args) {

/*
* Creating a HashMap Object and insert some key value pairs in it
*/
HashMap < String, String > m = new HashMap < String, String > ();
m.put("Marty", "Stepp");
m.put("Stuart", "Reges");
m.put("Jessica", "Miller");
m.put("Amanda", "Camp");
m.put("Hal", "Perkins");

//Synchronizing the HashMap Explicitly
Map map = Collections.synchronizedMap(m);
synchronized(m) {
Set < String > kys = m.keySet();
//Displaying the Keys
System.out.println(" Displaying the keys :");
for (String key: kys) {
System.out.println(key);
}

Set st = m.entrySet();
//Creating an Iterator Object
Iterator itr = st.iterator();
//Displaying the values
System.out.println("Displaying the values :");
while (itr.hasNext()) {
Map.Entry mp = (Map.Entry) itr.next();
System.out.println(mp.getValue());
}

}

}
}

____________________

Output:

Displaying the keys :
Hal
Marty
Stuart
Amanda
Jessica
Displaying the values :
Perkins
Stepp
Reges
Camp
Miller

_______________Thank You

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