INHERITANCE AND POLYMORPHISM - Java Programming: From Problem Analysis to Program Design - page 714

What is wrong with the following class definitions?
class BClass AClass
{

private int w;

public void print()
{

System.out.println("u + v + w = " + (u + v + w));

}

public BClass()
{

super ();
w = 0;

}

public BClass( int x, int y, int z)
{

super (x, y);
w = z;

}

}
10. Consider the following statements:
public class YClass
{

private int a;
private int b;

public void one()
{
}

public void two( int x, int y)
{
}

public YClass()
{
}

}

class XClass extends YClass
{

private int z;

public void one()
{
}

public XClass()
{
}

}