w3resource

Java Collection, HashSet Exercises: Compare two sets and retain elements which are same on both sets

Java Collection, HashSet Exercises: Exercise-11 with Solution

Write a Java program to compare two sets and retain elements which are same on both sets.

Sample Solution:

Java Code:

import java.util.*;
  public class Exercise11 {
  public static void main(String[] args) {
     // Create a empty hash set
        HashSet<String> h_set1 = new HashSet<String>();
     // use add() method to add values in the hash set
          h_set1.add("Red");
          h_set1.add("Green");
          h_set1.add("Black");
          h_set1.add("White");
          System.out.println("Frist HashSet content: "+h_set1);
          HashSet<String>h_set2 = new HashSet<String>();
          h_set2.add("Red");
          h_set2.add("Pink");
          h_set2.add("Black");
          h_set2.add("Orange");
          System.out.println("Second HashSet content: "+h_set2);
          h_set1.retainAll(h_set2);
          System.out.println("HashSet content:");
          System.out.println(h_set1);
     }
}

Sample Output:

Frist HashSet content: [Red, White, Black, Green]                      
Second HashSet content: [Red, Pink, Black, Orange]                     
HashSet content:                                                       
[Red, Black]

Pictorial Presentation:

Java Collection, ArrayList Exercises: Compare two sets and retain elements which are same on both sets

Flowchart:

Flowchart: Compare two sets and retain elements which are same on both sets.

Java Code Editor:

Contribute your code and comments through Disqus.

What is the difficulty level of this exercise?



Java: Tips of the Day

Try and catch:

Java is excellent at catching errors, but it can only recover gracefully if you tell it what to do. The cascading hierarchy of attempting to perform an action in Java starts with try, falls back to catch, and ends with finally. Should the try clause fail, then catch is invoked, and in the end, there's always finally to perform some sensible action regardless of the results. Here's an example:

try {
        cmd = parser.parse(opt, args); 
       
        if(cmd.hasOption("help")) {
                HelpFormatter helper = new HelpFormatter();
                helper.printHelp("Hello ", opt);
                System.exit(0);
                }
        else {
                if(cmd.hasOption("shell") || cmd.hasOption("s")) {
                String target = cmd.getOptionValue("tgt");
                } // else
        } // fi
} catch (ParseException err) {
        System.out.println(err);
        System.exit(1);
        } //catch
        finally {
                new Hello().helloWorld(opt);
        } //finally
} //try

It's a robust system that attempts to avoid irrecoverable errors or, at least, to provide you with the option to give useful feedback to the user. Use it often, and your users will thank you!

Ref: https://red.ht/3EZc9OC