Fill an Empty Array with Numbers Example in Java

Introduction

Fill an empty array with numbers is a classic Java console program that demonstrates the concept with complete source code and sample output. Arrays store fixed-size sequences with fast index access — a foundation before collections.

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 array is a way of storing several items (such as integers). These items must have the same type (only integers, only strings, …) because an array can not store different kinds of items. Every item in an array has a number so the programmer can get the item by using that number. This number is called the index. The first item has index 0, the second item has index 1 and so on.

Syntax

 Data_type[] Variable_name={value1, value2, ......};

Fill an empty array with numbers Example Program

import java.util.Arrays;

public class ArrayFill {
    public static void main(String[] args) {
		int[] values = new int[10];
		Arrays.fill(values, 5);
		for (int value : values) {
			System.out.print(value);
			System.out.print(' ');
		}
    }
}

Sample Output

5 5 5 5 5 5 5 5 5 5

When to use

Use this fill an empty array with numbers 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.Arrays; imports a class used later in the program.

3. int[] values = new int[10]; 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. Compare your console output with the sample output for Fill an empty array with numbers 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.