The java.util.Arrays Utility Class (sort, binarySearch, toString, copyOf)

Beginner13 min read•Updated: 2026-10-22

🛠️ The java.util.Arrays Utility Class

Introduction

The java.util.Arrays class provides static helper methods to manipulate, sort, search, format, and clone arrays without writing manual algorithms.

📚 Essential Methods

1import java.util.Arrays;
2 
3public class ArraysUtilDemo {
4    public static void main(String[] args) {
5        int[] numbers = {45, 12, 89, 33, 7, 62};
6 
7        // 1. Formatting Array to String:
8        System.out.println("Original: " + Arrays.toString(numbers));
9 
10        // 2. Sorting using Dual-Pivot Quicksort:
11        Arrays.sort(numbers);
12        System.out.println("Sorted:   " + Arrays.toString(numbers));
13 
14        // 3. Binary Search (Prerequisite: Array must be sorted!):
15        int target = 33;
16        int idx = Arrays.binarySearch(numbers, target);
17        System.out.println("Index of " + target + ": " + idx);
18 
19        // 4. Copying and Resizing:
20        int[] expanded = Arrays.copyOf(numbers, 10);
21        System.out.println("Expanded (length 10): " + Arrays.toString(expanded));
22 
23        // 5. Fill with constant:
24        int[] initialized = new int[5];
25        Arrays.fill(initialized, -1);
26        System.out.println("Filled with -1: " + Arrays.toString(initialized));
27    }
28}

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Two-Dimensional Arrays (Matrices) and Jagged Arrays	String Creation, String Pool, and Immutability in Java

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String Creation, String Pool, and Immutability in Java

The java.util.Arrays Utility Class (sort, binarySearch, toString, copyOf)

Beginner13 min read•Updated: 2026-10-22

Study Materials

🛠️ The java.util.Arrays Utility Class

Introduction

The java.util.Arrays class provides static helper methods to manipulate, sort, search, format, and clone arrays without writing manual algorithms.

📚 Essential Methods

1import java.util.Arrays;
2 
3public class ArraysUtilDemo {
4    public static void main(String[] args) {
5        int[] numbers = {45, 12, 89, 33, 7, 62};
6 
7        // 1. Formatting Array to String:
8        System.out.println("Original: " + Arrays.toString(numbers));
9 
10        // 2. Sorting using Dual-Pivot Quicksort:
11        Arrays.sort(numbers);
12        System.out.println("Sorted:   " + Arrays.toString(numbers));
13 
14        // 3. Binary Search (Prerequisite: Array must be sorted!):
15        int target = 33;
16        int idx = Arrays.binarySearch(numbers, target);
17        System.out.println("Index of " + target + ": " + idx);
18 
19        // 4. Copying and Resizing:
20        int[] expanded = Arrays.copyOf(numbers, 10);
21        System.out.println("Expanded (length 10): " + Arrays.toString(expanded));
22 
23        // 5. Fill with constant:
24        int[] initialized = new int[5];
25        Arrays.fill(initialized, -1);
26        System.out.println("Filled with -1: " + Arrays.toString(initialized));
27    }
28}

Next Lesson

String Creation, String Pool, and Immutability in Java

Continue learning with hands-on practice, examples, and exercises in the upcoming topic.

Related Lessons

Previous Lesson	Next Lesson
Two-Dimensional Arrays (Matrices) and Jagged Arrays	String Creation, String Pool, and Immutability in Java

Practice Quiz

Test your understanding of this lesson with 1 questions. Each question has one correct answer.

Previous Next