O que é String?

String and How to Use It

In Java, a String is a data type used to represent text. Its syntax looks like this:

Main


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String name = "string";

You've already encountered a String when you displayed something on the screen using double quotation marks (""). A string can also be output like any other variable, for example:

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package com.example;

public class Main {
    public static void main(String[] args) {
        // Initializing a String variable
        String hello = "Hello world!"; 
        // Printing the String variable
        System.out.println(hello);
    }
}

It looks simple. Well, let's move on to the challenging part then. A string is a data type that cannot be changed after initialization. This is called an immutable class. Don't get stuck on these intimidating words right now; we will discuss them in a separate course. We can directly modify the value of an already initialized string variable, but in doing so, we simply create a new object in memory. For example:

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package com.example;

public class Main {
    public static void main(String[] args) {
        // Initializing a String variable
        String hello = "Hello world!"; 
        // Changing the reference to a new object in heap memory
        hello = "Hello c<>definity";        
        // Printing the updated String variable
        System.out.println(hello);
    }
}

We can also create arrays of strings:

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package com.example;

public class Main {
    public static void main(String[] args) {
        String[] array = {"Hello", ", ", "c<>definity"};
        for (String element : array) {
            System.out.print(element);
        }
    }
}

In the next chapter, we will delve into the fundamental methods for working with strings, and you will come to understand why I mentioned that the value of a string variable cannot be altered without specific operations.

The image illustrates how the string "Codefinity" is broken down into characters with their corresponding indices. Indexing starts at zero, where C is at index 0, and the last character, y, is at index 9.

This structure makes it easy for developers to work with individual characters in a string using methods from the String class, which we will explore in the next chapter.

1. Will the following code compile?

2. Will the following code compile?

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Seção 5. Capítulo 1