Deeper into String

How String actually works?

You already know what a String is and how to work with it. This chapter will cover the theoretical aspects of what lies inside a String.

Let's explore the underlying representation of String values in Java. Initially, String was implemented as an array of char values, which was straightforward and intuitive. However, it later transitioned to an array of byte values. Let's understand the rationale behind this change.

A char variable in Java occupies 2 bytes of memory, while a byte variable only requires 1 byte. By utilizing byte values, we can significantly reduce the memory footprint, utilizing only one-fourth of the space.

But how does a String accommodate various characters, including non-numeric ones? The mechanism is akin to that of a char variable. We leverage the ASCII table, where numerical data is mapped to specific characters, enabling the representation of a wide range of characters in a String.

Let's take a look at an illustration representing the String value "Hello":

The cells contain type byte elements, which we take from the ASCII table. We can even view in the code the exact byte array that is stored in the value of a String variable. This can be done using the getBytes() method.

Main.java


              12345678910111213141516
            
package com.example;

public class Main {
    public static void main(String[] args) {
        String hello = "Hello";
        byte[] bytes = hello.getBytes();
        printArray(bytes);
    }

    static void printArray(byte[] bytes) {
        for (byte element: bytes) {
            System.out.print(element + " ");
        }
        System.out.println();
    }
}

We can see that the byte values are identical to those shown in the diagram above. Additionally, if you're interested, you can refer to the ASCII table and compare the code of each element with its corresponding value.

We can manipulate this byte[] array that we obtain from a String object.

¿Todo estuvo claro?

¡Gracias por tus comentarios!

Sección 3. Capítulo 1

Pregunte a AI

Pregunte lo que quiera o pruebe una de las preguntas sugeridas para comenzar nuestra charla

Contenido del Curso

Java Extended

1. Deep Java Structure

How Does the Compiler Works?Data Transfer in Java Final Keyword Importing Libraries Using Libraries In Our Code Ternary Operator Enhanced Switch Statement

2. Methods

What is a Method?Creating Our Own Methods Challenge: Names Starting with Letter B Void Methods Practice Method Overloading Recursion Challenge: Find Maximum and Minimum in Array

3. String Advanced

Deeper into String Method split()Challenge: Uppercase Even Words indexOf() Method Challenge: Finding the Longest Word trim() Method Challenge: Email Validation

4. Classes

5. Classes Advanced

Complex Classes Usage Challenge: Pet and Owner Relationship Private Modifier Challenge: Animal Information Display Getter and Setter Challenge: Updating User Information Summary