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This exercise deliberately demonstrates two scenarios where super fails — understanding these errors prevents confusion when the compiler rejects seemingly reasonable code. Rather than showing only working programs, Ejercicio 3 keeps the broken lines commented in the source so you can see exactly what you must not write, alongside the correct alternative in each case. Both errors stem from the same root cause: super is a reference tied to a specific object instance, so anything that removes that instance context — a static method, or a private access barrier — makes super unusable.

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Pitfall 1: super in a Static Context

Inside MainEjercicio3.main(), the following line is commented out: 
// super.toString(); // Error de compilación: 'super' cannot be used in a static context
main is declared static, meaning it belongs to the class itself rather than to any particular object. There is no this reference, and therefore no parent portion of an object to refer to. The compiler produces: 
error: non-static variable super cannot be referenced from a static context
The runtime equivalent would also be nonsensical: there is no object in scope whose parent class fields could be read. The working code in main instead prints an explanatory message and then delegates to an instance method where super is valid: 
public static void main(String[] args) {
    // super.toString(); // Error de compilación: 'super' cannot be used in a static context
    System.out.println("Demostración de uso incorrecto de 'super' en un contexto no derivado (como main): No compila.");
    System.out.println("El error sería: 'super' cannot be used in a static context");

    ClaseDerivada objDerivado = new ClaseDerivada();
    objDerivado.intentarAccederAtributoPrivado();
}
Even inside a subclass, if the method is static, super is forbidden. This rule applies universally — not just in main.

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Pitfall 2: Accessing Private Fields via super

ClaseBase declares two fields with different access modifiers:
FieldModifierSubclass can read via super?
atributoPrivadoprivate❌ No
atributoProtegidoprotected✅ Yes
Inside ClaseDerivada.intentarAccederAtributoPrivado(), this line is commented out because it will not compile: 
// super.atributoPrivado; // Esto causaría un error de compilación: atributoPrivado tiene acceso privado
The compiler error would be: 
error: atributoPrivado has private access in ClaseBase
private means the field is encapsulated within ClaseBase only — not even its own subclasses can bypass that boundary. The correct approach is to call the public getter super.getAtributoPrivado(), which ClaseBase exposes precisely for this purpose.

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Full Source

Taller9/MainEjercicio3.java
package Taller9;

class ClaseBase {
    private String atributoPrivado = "Soy privado";
    protected String atributoProtegido = "Soy protegido";

    public String getAtributoPrivado() {
        return atributoPrivado;
    }
}

class ClaseDerivada extends ClaseBase {
    public void intentarAccederAtributoPrivado() {
        // super.atributoPrivado; // Esto causaría un error de compilación: atributoPrivado tiene acceso privado
        System.out.println("Intentando acceder a atributoPrivado de la clase base (incorrecto): No se puede acceder directamente.");
        System.out.println("Accediendo a atributoProtegido de la clase base (correcto): " + super.atributoProtegido);
        System.out.println("Accediendo a atributoPrivado a través de un getter (correcto): " + super.getAtributoPrivado());
    }
}

public class MainEjercicio3 {
    public static void main(String[] args) {
        // 1. Intentar utilizar super en un contexto que no sea una clase derivada
        // super.toString(); // Error de compilación: 'super' cannot be used in a static context
        System.out.println("Demostración de uso incorrecto de 'super' en un contexto no derivado (como main): No compila.");
        System.out.println("El error sería: 'super' cannot be used in a static context");

        ClaseDerivada objDerivado = new ClaseDerivada();
        objDerivado.intentarAccederAtributoPrivado();
    }
}

​
Expected output

Demostración de uso incorrecto de 'super' en un contexto no derivado (como main): No compila.
El error sería: 'super' cannot be used in a static context
Intentando acceder a atributoPrivado de la clase base (incorrecto): No se puede acceder directamente.
Accediendo a atributoProtegido de la clase base (correcto): Soy protegido
Accediendo a atributoPrivado a través de un getter (correcto): Soy privado

​
Summary: What super Can and Cannot Access

Member typeAccessible via super?Alternative
public field✅ Yes—
protected field✅ Yes—
private field❌ NoUse a public/protected getter
Any member in a static method❌ NoN/A — super requires an instance context

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Compile & Run

# From the project root (parent of the Taller9/ directory)
javac Taller9/MainEjercicio3.java
java Taller9.MainEjercicio3
ClaseBase and ClaseDerivada are package-private classes defined in the same file as MainEjercicio3, so a single javac command compiles all three.

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