Class

A class is the blueprint for creating objects, it defines the structure and behavior that objects will have.

Basic Structure

public class ClassName {
  // Fields (attributes)
  private int myField;

  // Constructor
  public ClassName() {
    // Initialize fields
  }

  // Methods
  public void myMethod() {
    // Method implementation
  }
}

Components

1. Class Declaration: Starts with optional access modifier, followed by the keyword class and the class name
2. Fields: Variables that belong to the class
3. Constructors: Special methods used to initialize objects
4. Methods: Functions that define the behavior of the class

Example

public class Person {
  // Fields
  private String name;
  private int age;

  // Constructor
  public Person(String name, int age) {
    this.name = name;
    this.age = age;
  }

  // Getter methods
  public String getName() {
    return name;
  }

  public int getAge() {
    return age;
  }

  // Method
  public void introduceYourself() {
    System.out.println("Hello, my name is " + name + " and I am " + age + " years old.");
  }
}

Constructors

A constructor is a special method in a class that is called when an object is created.

• It is used to initialize the object’s fields.
• Constructors have the same name as the class and do not have a return type.

public class Car {
  private String model;

  // Constructor
  public Car(String model) {
    this.model = model;
  }

  public void showInfo() {
    System.out.println("Model: " + model);
  }
}

// Usage:
Car car = new Car("Toyota");
car.showInfo(); // Output: Model: Toyota

Best Practices

• Class names should start with a capital letter
• Follow camelCase naming convention
• Keep classes focused on a single responsibility
• Properly encapsulate fields using private access and public getter/setter methods