Java Docs: Classes & Objects

Java Docs: Classes & Objects
0.0 0

#1

Java Classes & Objects

Classes are groups of variables and operations on them. A class can have variables, methods (or functions) and constructors (or methods which are used to initiate, more on that later!).

Think of a Class as a blueprint for creating something concrete. A Class tells you the ‘what’ and ‘how’ an object of that Class will look like once instantiated. In essence, it defines properties (say color, engine capacity) and behavior (stop, speed up, change gears, honk etc.) for a Car in this case.

Objects are instances of a class. All objects are instances of a certain class. Imagine a class being a “template”, which every Object copies to. When you create an Object, basically it creates a new object on the blueprint of a class. Now lets look at this from a little piece of code :

// Car class
public class Car {
  // car name
  private String name;
    // car mannufacturer name
    private String manufacturerName;
  // constructor
    public Car(String name, String man) {
        this.name = name;
        this.manufacturerName = man;
    }
  // getter method
    public String getName() {
        return name;
    }
  // getter method
    public String getManufacturerName() {
        return manufacturerName;
    }

  //setter method
  public void setName(String name){
     this.name = name;
  }
}

Car modelS = new Car("Model S","Tesla");

System.out.println("Full Car Name = " + modelS.getManufacturerName() + " " + modelS.getName());
// prints Tesla Model S

:rocket: Run Code

So, Car is a class, which has the fields or properties name and manufacturerName. modelS is an object of Car class. So modelS also has the same properties and methods.


#2