Problems

Coupling
Maintainability

Solutions

Favor composition.

Exceptions

If hierarchy follows the principle behaves like then it is safe.

Sample Code

Wrong

public class Rectangle {

    int length;
    int width;

    public Rectangle(int length, int width){
        length = length;
        width = width;
    }

    public int area(){
        return length * width;
    }
}

public class Square extends Rectangle {

     public Square(int size){
        super(size, size); 
    }

    public int area(){
        return length * length;
    }
}

public class Box extends Rectangle{    

}

Right

abstract public class Shape{

    abstract public int area();
}

public final class Rectangle extends Shape {

    int length;
    int width;

    public Rectangle(int length, int width){
        length = length;
        width = width;
    }

    public int area(){
        return length * width;
    }
}

public final class Square extends Shape {

     int size;

     public Square(int size){
        size = size; 
    }

    public int area(){
        return size * size;
    }
}

public final class Box {

    Square shape;

    public Box(int size){
        shape = new Square(size); 
    }

    public int area(){
        return shape.area();
    }
}

Detection

Overriding can issue warnings when subclassing concrete methods.
Deep Hierarchies (more than 3 levels) are also a clue of bad subclassing.

Conclusion

In legacy systems is very common to have Deep Hierarchies and method overriding, we need to refactor them and subclass by essential reasons and not implementative ones.