Java interview questions Part21

1.
Which statement(s) are true? (Choose all that apply.)

Has-a relationships always rely on inheritance.

Has-a relationships always rely on instance variables.

Has-a relationships always require at least two class types.

Has-a relationships always rely on polymorphism.

Has-a relationships are always tightly coupled.


2.
Given:

class Clidders {
public final void flipper() { System.out.println("Clidder"); }
}
public class Clidlets extends Clidders {
public void flipper() {
System.out.println("Flip a Clidlet");
super.flipper();
}
public static void main(String [] args) {
new Clidlets().flipper();
}
}

What is the result?

Flip a Clidlet

Flip a Clidder

Flip a Clidder

Flip a Clidlet

Flip a Clidlet

Flip a Clidder

Compilation fails.


3.
Given:

public abstract interface Frobnicate { public void twiddle(String s) ; }

Which is a correct class? (Choose all that apply.)

public abstract class Frob implements Frobnicate {

public abstract void twiddle(String s){}

}

public abstract class Frob implements Frobnicate { }

public class Frob extends Frobnicate {

public void twiddle(Integer i) { }

}

public class Frob implements Frobnicate {

public void twiddle(Integer i) { }

}

public class Frob implements Frobnicate {

public void twiddle(String i) { }

public void twiddle(Integer s) { }

}


4.
Given:

class Top {
public Top(String s) { System.out.print("B"); }
}
public class Bottom2 extends Top {
public Bottom2(String s) { System.out.print("D"); }
public static void main(String [] args) {
new Bottom2("C");
System.out.println(" ");
}
}

What is the result?

BD

DB

BDC

DBC

Compilation fails.


5.
Select the two statements that best indicate a situation with low coupling. (Choose two.)

The attributes of the class are all private.

The class refers to a small number of other objects.

The object contains only a small number of variables.

The object is referred to using an anonymous variable, not directly.

The reference variable is declared for an interface type, not a class. The interface provides a small number of methods.

It is unlikely that changes made to one class will require any changes in another.


6.
Given:

class Clidder {
private final void flipper() { System.out.println ("Clidder"); }
}

public class Clidlet extends Clidder {
public final void flipper() { System.out.println("Clidlet"); }
public static void main(String [] args) {
new Clidlet().flipper();
}
}

What is the result?

Clidlet

Clidder

Clidder

Clidlet

Clidlet

Clidder

Compilation fails.