Clear an Arraylist Example in Java

Introduction

Clear an Arraylist is a classic Java console program that demonstrates the concept with complete source code and sample output. The Collections Framework provides ArrayList, HashMap, HashSet and related data structures.

This tutorial walks through the program line by line, explains how the logic works, and highlights best practices you can apply in your own code.

Definition

An ArrayList is a non-syncronized class. It implements List Interface and inherits AbstractList class. It maintains insertion order.

Syntax

arraylist.clear();

Clear ArrayList Example Program

import java.util.ArrayList;

class ClearArrayListExample{
	public static void main(String[] args){
		ArrayList<String> directionsArraylist = new ArrayList<String>();
		//Adding elements to arraylist
		directionsArraylist.add("NORTH");
		directionsArraylist.add("SOUTH");
		directionsArraylist.add("EAST");
		directionsArraylist.add("WEST");
		
		System.out.println("The arraylist is : "+directionsArraylist);
		System.out.println("The size of the arraylist is : "+directionsArraylist.size()); //Printing size of arraylist
		
		directionsArraylist.clear();//Clearing the arraylist or Removing all items in the arraylist
		
		System.out.println("The size of the arraylist after clearing is : "+directionsArraylist.size());//Printing size of arraylist
	}
}

Sample Output

The ArrayList is : [NORTH, SOUTH, EAST, WEST]
The size of the ArrayList is: 4
The size of the ArrayList after clearing is : 0

When to use

Use this clear an arraylist example when learning or revising core Java syntax.

How it works

1. Execution begins in the main method — the JVM calls this method when you run the class.

2. import java.util.ArrayList; imports a class used later in the program.

3. ArrayList<String> directionsArraylist = new ArrayList<String>(); updates a variable used in the calculation or output.

4. A println / print call writes text to the console — part of the sample output below.

5. A println / print call writes text to the console — part of the sample output below.

6. A println / print call writes text to the console — part of the sample output below.

7. Compare your console output with the sample output for Clear an Arraylist to confirm the program behaves correctly.

Best Practices

• Use meaningful variable and class names that describe their purpose.
• Compile and run the program locally — modify values to see how output changes.
• Read compiler errors carefully; they usually point to the exact line to fix.

Common Mistakes

• Copying code without understanding each line — practice by changing one statement at a time.
• Mismatching the public class name and the .java filename.
• Forgetting semicolons at the end of statements.