Merge Two Arrays Example in Java

Introduction

Merge Two Arrays 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.

Merge Two Arrays Example Program

import java.util.Arrays;

public class MergeTwoArrays {
    public static void main(String[] args) {
	System.out.println("The first array is: ");
	int[] values1 = { 10, 20, 30 };
	for(int i=0;i < values1.length;i++){
	System.out.println(values1[i]);
	}
	System.out.println("The second array is: ");
	int[] values2 = { 100, 200, 300 };
	for(int i=0;i < values2.length;i++){
	System.out.println(values2[i]);
	}
	int[] merge = new int[values1.length + values2.length];
	for (int i = 0; i < values1.length; i++) {
	    merge[i] = values1[i];
	}
	for (int i = 0; i < values2.length; i++) {
	    merge[i + values1.length] = values2[i];
	}
	System.out.println("The merged array is: ");
	System.out.println(Arrays.toString(merge));
    }
}

Sample Output

The first array is:
10
20
30
The second array is:
100
200
300
The merged array is:
[10, 20, 30, 100, 200, 300]

When to use

Use this merge two arrays 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. A println / print call writes text to the console — part of the sample output below.

4. int[] values1 = { 10, 20, 30 }; updates a variable used in the calculation or output.

5. A loop repeats the block until its condition becomes false.

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

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

8. A loop repeats the block until its condition becomes false.

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.