Conteúdo do 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 Sorting Even Numbers Challenge

3. String Advanced

Deeper into String Method split()Uppercase Even Words Challenge indexOf() method Character Indices Sum Challenge trim() Method Substring First and Last Characters Challenge

4. Classes

What is class?Main Class and Method Access modifiers Class Creation Cat Meowing Challenge Constructor Team Constructor Challenge Method toString()Parrot Information Display Challenge

5. Classes Advanced

Complex Classes Usage Pet and Owner Relationship Challenge Private Modifier Animal Information Display Challenge Getter and Setter Country Information Management Challenge Summary

Summary

Congrats!

Congratulations on completing the second Java course! This course has been extensive and filled with practical exercises, but each of us has to go through trials in pursuit of success.

Let's summarize the key points from the entire course in this chapter!

Section 1:

JVM - Java Virtual Machine. This machine translates machine code into bytecode and vice versa. It enables the language's platform independence and performance;
JRE - Java Runtime Environment. It is a set of tools required for writing and running code. It includes JVM, compiler, and editor;
JDK - Java Development Kit. It is a comprehensive set of tools needed for Java programming. It includes JRE, JVM, external libraries, and more;
import: The import keyword is used to include classes or packages from external libraries or other Java source files. It allows you to use the classes, interfaces, and other members defined in those imported packages or files without fully qualifying their names:

Main


              12
            
import parent.Child;
import parent.*;

final: The final keyword is used to declare that a variable, method, or class cannot be changed or overridden. When applied to a variable, it makes the variable a constant that cannot be reassigned. When applied to a method, it prevents the method from being overridden in subclasses. When applied to a class, it makes the class unextendable, meaning it cannot be subclassed:

Main


              1
            
final int constant = 10;

Ternary operator - a simplified version of an if statement that can be used as a return type:

Main


              1
            
condition ? true : false

Enhanced Switch - a simplified version of the switch statement with slightly modified syntax and no need for the break keyword:

Main


              123456789101112
            
switch (variable) {
    case value1 -> {
        // code block
    }
    case value2 -> {
        // code block
    }
    // additional cases
    default -> {
        // code block
    }
}

Section 2:

Method: In Java, a method is a block of code that performs a specific task. It is a reusable piece of code that can be called and executed whenever needed. Methods are used to organize code, improve code reusability, and make programs easier to understand and maintain. They can accept input parameters, perform operations, and optionally return a value;
Methods are defined within a class and can be called by their name followed by parentheses. When a method is called, the program execution jumps to that method, executes the code inside it, and then returns back to the calling code:

Main


              123
            
ReturnType MethodName(ParameterType parameter, ParameterType parameter) {
     // code that will be executed when we will call this method
}

Method Overloading: Method overloading in Java allows us to define multiple methods with the same name but with different parameters. These methods can have different parameter types, different number of parameters, or both. When a method is called, the Java compiler determines the appropriate method to execute based on the arguments provided. Method overloading provides flexibility and allows us to use the same method name for similar operations with different inputs;
Recursion: Recursion is a programming technique where a method calls itself to solve a problem by breaking it down into smaller subproblems. In a recursive method, the method continues to call itself until it reaches a base case, which is a condition that stops the recursive calls. Recursion is useful for solving problems that can be divided into smaller, repetitive tasks. However, it's important to ensure that there is a proper base case to avoid infinite recursion.

Section 3:

String is an array of bytes;

split: The split method is used to split a string into an array of substrings based on a specified delimiter. It takes a regular expression as an argument and returns an array of strings;
indexOf: The indexOf method is used to find the index of the first occurrence of a specified character or substring within a string. It returns the index as an integer value. If the character or substring is not found, it returns -1;
lastIndexOf: The lastIndexOf method is similar to indexOf, but it searches for the last occurrence of a specified character or substring within a string. It also returns the index as an integer value;
trim: The trim method is used to remove leading and trailing whitespace from a string. It returns a new string with the whitespace removed.

Section 4:

Class: In Java, a class is a blueprint or template that defines the properties (variables) and behaviors (methods) that objects of that class will have. It serves as a blueprint for creating objects:

Name


              123
            
class Name {
    //fields and methods
}

Main Method: The main method is a special method in Java that serves as the entry point for a Java program. It is the starting point from which the program execution begins. The main method must have a specific signature and is typically declared as public static void main(String[] args);
Main Class: The main class is the class that contains the main method. It is the class from which the Java program is executed. It is identified by the Java runtime environment and is required for running the program;
Constructor: A constructor is a special method that is used to initialize objects of a class. It has the same name as the class and is called when an object is created using the new keyword. Constructors are used to set initial values to the instance variables of the class:

Main


              1234
            
modifier ClassName(ParameterType parameter1, ParameterType parameter2) {
        this.parameter1 = parameter1;
        this.parameter2 = parameter2;
}

toString Method: The toString method is a method defined in the Object class, which is the root class for all Java classes. It is used to provide a string representation of an object. By overriding the toString method in a class, you can customize how the object is represented as a string:

Main


              1234
            
	@Override
    public String toString() {
        // block of code
    }

Section 5:

Private Modifier: The private modifier is an access modifier in Java that restricts the visibility of a class member (variables or methods) to only within the same class. It means that the member can only be accessed and modified by other members within the same class and is not accessible outside the class:

Main


              1
            
private int privatVariable;

Getters and Setters: Getters and setters are methods used to access and modify the values of private variables in a class, respectively. They provide an indirect way of accessing and modifying the private variables of a class, ensuring encapsulation and data hiding. Getters are used to retrieve the value of a private variable, while setters are used to set or update the value of a private variable:

Main


              123456789
            
    // getter
    public fieldType getFieldName() {
        return field;
    }

    //setter
    public void setFieldName(fieldType field) {
        this.field = field;
    }

If you have completed this course, there is no turning back. You should definitely consider becoming a Java programmer. The next step in learning the language is Object-Oriented Programming (OOP), which is probably the most challenging topic for all programmers. I wish you good luck, and thank you for choosing our platform for your learning journey!

Tudo estava claro?

Seção 5. Capítulo 7