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Java Collection, ArrayList Exercises: Replace the second element of a ArrayList with the specified element

Java Collection, ArrayList Exercises: Exercise-21 with Solution

Write a Java program to replace the second element of a ArrayList with the specified element.

Pictorial Presentation:

Java Collection, ArrayList Exercises: Replace the second element of a ArrayList with the specified element.

Sample Solution:-

Java Code:

import java.util.ArrayList;
  public class Exercise21 {
    public static void main(String[] args){
  ArrayList<String>  color = new ArrayList<String>();

  color.add("Red");
  color.add("Green");

  System.out.println("Original array list: " + color);
  String new_color = "White";
  color.set(1,new_color);

  int num=color.size();
  System.out.println("Replace second element with 'White'."); 
  for(int i=0;i<num;i++)
  System.out.println(color.get(i));
  }
}

Sample Output:

Original array list: [Red, Green]                                      
Replace second element with 'White'.                                   
Red                                                                    
White

Flowchart:

Flowchart: Replace the second element of a ArrayList with the specified element.

Java Code Editor:

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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