w3resource

Java Collection, ArrayList Exercises: Retrieve an element from a given array list

Java Collection, ArrayList Exercises: Exercise-4 with Solution

Write a Java program to retrieve an element (at a specified index) from a given array list.

Pictorial Presentation:

Java Collection, ArrayList Exercises: Retrieve an element from a given list

Sample Solution:-

Java Code:

import java.util.*;
  public class Exercise4 {
  public static void main(String[] args) {
  // Creae a list and add some colors to the list
  List<String> list_Strings = new ArrayList<String>();
  list_Strings.add("Red");
  list_Strings.add("Green");
  list_Strings.add("Orange");
  list_Strings.add("White");
  list_Strings.add("Black");
  // Print the list
  System.out.println(list_Strings);
  // Retrive the first and third element
  String element = list_Strings.get(0);
  System.out.println("First element: "+element);
  element = list_Strings.get(2);
  System.out.println("Third element: "+element);
 }
}

Sample Output:

[Red, Green, Orange, White, Black]                                     
First element: Red                                                     
Third element: Orange

Flowchart:

Flowchart: Retrieve an element from a given list.

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