JAVA PROGRAM • LEVEL 13 — COLLECTIONS & GENERICS

Update and Remove ArrayList Elements in Java

Learn update and remove arraylist elements in java with a complete, compiler-ready Java 17 example.

Intermediateset()remove()

PROBLEM UNDERSTANDING

Input and expected output

Sample input

No input required

Sample output

[25, 30]

COMPLETE JAVA 17 PROGRAM

Complete Java 17 implementation

import java.util.*;

class Main {
    public static void main(String[] args) throws Exception {
        List<Integer> values=new ArrayList<>(List.of(10,20,30));
        values.set(1,25);values.remove(Integer.valueOf(10));
        System.out.println(values);
    }
}

CURRENT STEP

Select Start to walk through the important lines.

SELECTED LINE

No line selected

EXPECTED OUTPUT FOR THE SAMPLE

[25, 30]

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Initialize the deterministic sample values used for update and remove arraylist elements in java.
Create the required object and apply set() and remove() to its state or behavior.
Print the final result and compare it with the documented sample output.

This Java 17 example demonstrates set() and remove() through a complete, executable program. The values are intentionally small so students can trace each statement, verify the output, and then modify the example safely in the online compiler.

EFFICIENCY

Time and space complexity

Time complexity

O(n)

Auxiliary space

O(n)

DEBUGGING CHECKLIST

Common mistakes

Check this

Keep the class name Main and the entry method signature public static void main(String[] args) when using the online compiler.

Check this

Use set() with compatible Java types; Java checks types and method signatures at compile time.

Check this

Java is case-sensitive, and every statement that requires a semicolon must end with one.

Try it yourself

Practice: Run the program with the sample input, predict its output, and then test one boundary case of your own.