Java Arrays and Strings Explained in Depth with Examples

Java Arrays and Strings Explained in Depth

Author: Gursehbaj Singh | Blog: DevMode

Arrays and Strings are two of the most important topics in Java. They are used to store multiple values and text data. In this guide, you will learn them deeply with simple explanations and examples.

What is an Array?

An array is a collection of similar data stored in one variable.

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

Accessing Array Elements

System.out.println(numbers[0]); // 10
System.out.println(numbers[3]); // 40

Array Using Loop

for(int i = 0; i < numbers.length; i++) {
    System.out.println(numbers[i]);
}

Two-Dimensional Array

int[][] matrix = {
    {1, 2, 3},
    {4, 5, 6}
};

What is a String?

A String is a sequence of characters.

String name = "DevMode";

Common String Methods

String text = "Java Programming";

System.out.println(text.length());
System.out.println(text.toUpperCase());
System.out.println(text.toLowerCase());
System.out.println(text.charAt(0));
System.out.println(text.contains("Java"));

Comparing Strings

String a = "Java";
String b = "Java";

System.out.println(a.equals(b));

String Concatenation

String first = "Hello";
String second = "World";
String result = first + " " + second;

StringBuilder (Mutable String)

StringBuilder sb = new StringBuilder("Hello");
sb.append(" Java");
System.out.println(sb.toString());

Conclusion

Arrays help you store multiple values, and Strings help you work with text. Mastering them is very important for building real Java programs.