FragileBaseClassProblem.java

import java.util.ArrayList;

interface IArray {
  public void add(Object element);
  public void addAll(Object elements[]);
}

class Array implements IArray {
  private ArrayList<Object> a = new ArrayList<Object>();

  public void add(Object element) {
    a.add(element);
  }

  public void addAll(Object elements[]) {
    for (int i = 0; i < elements.length; ++i)
      a.add(elements[i]); // this line is going to be changed
  }
}

// Don't inherit from Array, instead use composition
class ArrayCount implements IArray {
  private int count = 0;
  private Array array = new Array();

  public void add(Object element) {
    array.add(element);
    ++count;
  }

  public void addAll(Object elements[]) {
    array.addAll(elements);
    count += elements.length;
  }
}