Lennart01 / JavaVsGoOO

Basic Inheritance

Source Files

• Java
• Go

Java

Java fully supports inheritance, which combines subtyping and virtual methods, using the extends keyword. Inheritance in Java allows for defining subtyping relationships, known as nominal subtyping. In our example, we create a Car class with two methods: vehicleType and brand. We then define Porsche and Audi classes that extend Car. Both classes override the brand method and introduce a new method, speed.

Go

Go does not support classic inheritance as seen in languages like Java. Instead, it uses a combination of struct embedding and interfaces to achieve polymorphic behavior, which is commonly achieved through inheritance in other languages.

Go employs structural subtyping. In Go:

• There are no classes, but rather structs and interfaces.
• Methods can be defined "freely" in the sense that they are not bound to a class hierarchy.
• Methods can be overloaded, meaning that the receiver type and the method name must uniquely determine the instance.
• Interfaces describe receivers that satisfy the methods contained within the interface.

In our example:

• We define a Vehicle interface with two methods: VehicleType and Brand.
• A Car struct is created as a generic car, implementing the Vehicle interface by providing VehicleType and Brand methods. In Go, interface implementation is implicit: any struct that provides the required methods is considered to implement the interface.
• Porsche and Audi structs are then defined, each embedding Car. This embedding allows them to inherit Car's methods and properties.
• Both Porsche and Audi introduce a Speed method and provide their own implementations of the Brand method, effectively overriding the Car's Brand method. This showcases how Go uses composition and method redefinition to achieve a similar outcome to what is typically achieved with classical inheritance.

Abstract Classes

Source Files

• Java
• Go

Java

In Java there are abstract classes. These can not be instantiated and require subclasses to implement their abstract methods.

Go

In Go there are no abstract classes and since there is no inheritance struct compositions can implement interfaces even if their parent struct does not (structural Subtyping).