Java Array Problems for Beginners

Introduction

Arrays are one of the most important data structures in Java. They help you store multiple values in a single variable, making it easy to organize and process large sets of data. If you want to become strong in Java programming, mastering arrays is essential.

In this article, we’ll explore a collection of beginner-level Java array problems that focus on topics like finding maximum and minimum values, summing elements, sorting, and reversing arrays. These problems will enhance your logic-building and prepare you for data structure and algorithm challenges.

🧠 Problem Set — Java Array Challenges

🧩 Problem 1: Find the Largest Element in an Array

Description:

Write a Java program to find the largest number in a given integer array.

Example Input:

[10, 45, 32, 67, 89]

Example Output:

Largest Element: 89

Hint:

Initialize a variable with the first element and compare it with every other element in the array.

Sample Code:

public class LargestElement {

public static void main(String[] args) {

int[] arr = {10, 45, 32, 67, 89};

int max = arr[0];

for (int num : arr) {

if (num > max)

max = num;

}

System.out.println("Largest Element: " + max);

}

}

🧩 Problem 2: Find the Smallest Element in an Array

Description:

Write a Java program to find the smallest element in an array.

Example Input:

[25, 13, 47, 2, 19]

Example Output:

Smallest Element: 2

Hint:

Use logic similar to finding the maximum value, but compare using <.

Sample Code:

public class SmallestElement {

public static void main(String[] args) {

int[] arr = {25, 13, 47, 2, 19};

int min = arr[0];

for (int num : arr) {

if (num < min)

min = num;

}

System.out.println("Smallest Element: " + min);

}

}

🧩 Problem 3: Calculate the Sum of All Elements in an Array

Description:

Write a program that calculates the total sum of all the elements in an integer array.

Example Input:

[5, 10, 15, 20, 25]

Example Output:

Sum: 75

Hint:

Use a loop and an accumulator variable to add each element.

Sample Code:

public class ArraySum {

public static void main(String[] args) {

int[] arr = {5, 10, 15, 20, 25};

int sum = 0;

for (int num : arr) {

sum += num;

}

System.out.println("Sum: " + sum);

}

}

🧩 Problem 4: Reverse an Array

Description:

Write a Java program that reverses the elements of an array.

Example Input:

[10, 20, 30, 40, 50]

Example Output:

[50, 40, 30, 20, 10]

Hint:

Use two pointers — one starting from the beginning and the other from the end — and swap the values.

Sample Code:

public class ReverseArray {

public static void main(String[] args) {

int[] arr = {10, 20, 30, 40, 50};

int start = 0, end = arr.length - 1;

while (start < end) {

int temp = arr[start];

arr[start] = arr[end];

arr[end] = temp;

start++;

end--;

}

System.out.print("Reversed Array: ");

for (int num : arr) {

System.out.print(num + " ");

}

}

}

🧩 Problem 5: Sort an Array in Ascending Order

Description:

Write a Java program that sorts an array in ascending order.

Example Input:

[9, 4, 6, 3, 7]

Example Output:

[3, 4, 6, 7, 9]

Hint:

Use a simple sorting algorithm like Bubble Sort.

Sample Code:

public class SortArray {

public static void main(String[] args) {

int[] arr = {9, 4, 6, 3, 7};

for (int i = 0; i < arr.length - 1; i++) {

for (int j = 0; j < arr.length - i - 1; j++) {

if (arr[j] > arr[j + 1]) {

int temp = arr[j];

arr[j] = arr[j + 1];

arr[j + 1] = temp;

}

}

}

System.out.print("Sorted Array: ");

for (int num : arr) {

System.out.print(num + " ");

}

}

}

💡 Key Takeaways

• Through these five problems, you learned:
• How to iterate through arrays using loops.
• How to apply logic for finding max, min, and sum.
• How to reverse and sort arrays using basic algorithms.
• The importance of understanding array indices in Java.

Mastering these fundamentals will help you move on to intermediate-level challenges like searching algorithms, multi-dimensional arrays, and array-based data structure problems.

Stay tuned for the next post in this Java problem series:

👉 “Java Loop and Conditional Problems for Beginners — Build Strong Logic Step by Step.”

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