How to create this class hierarchy?

Question

In this exercise, I have to create a class within another class or are independent classes?

• An animal contains a name, length, number of legs (default is 4), one color, environment and a speed (in m/s).
• A fish is an animal, has 0 legs, its environment is the sea (standard), grey (standard). In addition, the fish has as characteristic: fins and tail;
• A mammal is an animal, its standard environment is the earth and has as characteristic: hair in all or in part of the body;
• A bear is a mammal, brown in color and its preferred food is honey and hair throughout body.

Code animal, fish, mammal and bear classes considering they all have a builder named.

Answer 1

This seems to be a POO exercise on inheritance, not to create one class within another, but to extend the child classes with the mother class. I implemented a version of my own here based on your descriptions.

This is the base class, I left all attributes as String for ease.

Java animal.

public class Animal {
    protected String nome, comprimento, patas, cor, ambiente, velocidade, caracteristica, alimentoPreferido;

    public Animal(String nome) {
        this.nome = nome;

        this.comprimento = "0m";
        this.patas = "0";
        this.cor = "Nenhuma";
        this.ambiente = "Nenhum";
        this.velocidade = "0m/s";
        this.caracteristica = "Nenhuma";
        this.alimentoPreferido = "Nenhum";
    }

    public String getNome() { return nome; }

    public void setNome(String nome) { this.nome = nome; }

    public String getComprimento() { return comprimento; }

    public void setComprimento(String comprimento) { this.comprimento = comprimento; }

    public String getPatas() { return patas; }

    public void setPatas(String patas) { this.patas = patas; }

    public String getCor() { return cor; }

    public void setCor(String cor) { this.cor = cor; }

    public String getAmbiente() { return ambiente; }

    public void setAmbiente(String ambiente) { this.ambiente = ambiente; }

    public String getVelocidade() { return velocidade; }

    public void setVelocidade(String velocidade) { this.velocidade = velocidade; }

    public String getCaracteristica() { return caracteristica; }

    public void setCaracteristica(String caracteristica) { this.caracteristica = caracteristica; }

    public String getAlimentoPreferido() { return alimentoPreferido; }

    public void setAlimentoPreferido(String alimentoPreferido) { this.alimentoPreferido = alimentoPreferido;    }
}

Subclass that extends animal inheriting its attributes and methods.

Java fish.

public class Peixe extends Animal {
    public Peixe(String nome) {
        super(nome);

        this.comprimento = "15cm";
        this.patas = "0";
        this.cor = "Cinzenta";
        this.ambiente = "Mar";
        this.velocidade = "2m/s";
        this.caracteristica = "Barbatanas e Cauda";
        this.alimentoPreferido = "Algas";
    }
}

Subclass that extends animal inheriting its attributes and methods.

Mamifero.java.

public class Mamifero extends Animal {
    public Mamifero(String nome) {
        super(nome);

        this.ambiente = "Terra";
        this.caracteristica = "Pelo em todo ou em parte do corpo";
    }
}

Subclass that extends Mamifero inheriting his attributes and methods.

Java bear.

public class Urso extends Mamifero {
    public Urso(String nome) {
        super(nome);

        this.comprimento = "1m";
        this.patas = "4";
        this.cor = "Castanho";
        this.velocidade = "1m/s";
        this.caracteristica = "Pelo em todo corpo";
        this.alimentoPreferido = "Mel";
    }
}

And a class to test Main.java

public class Main {
    public static void main(String[] args) {
        Animal animal = new Animal("Animal Base");
        Peixe peixe = new Peixe("Nemo");
        Mamifero mamifero = new Mamifero("Mamifero Base");
        Urso urso = new Urso("Zé Colmeia");

        System.out.println(animal.getNome());
        System.out.println(peixe.getPatas());
        System.out.println(mamifero.getCaracteristica());
        System.out.println(urso.getAlimentoPreferido());
    }
}