Create the classes:

package p2;
public class C {
  protected long getF(){
    return 0;
  }
  public long m(){
    return getF();
  }
}


package p2;
public class A extends C {
  public long f=10;
  public long test(){
    return m();
  }
}


apply the pull up field refactoring to B.f 

package p2;
public class C {
  protected long getF(){
    return 0;
  }
  public long m(){
    return getF();
  }
}


package p2;
public class A extends C {
  private long f=10;
  public long test(){
    return m();
  }

    public long getF() {
        return f;
    }

    public void setf(long f) {
        this.f = f;
    }
}


The transformation changes behavior. After the transformation the m method
returns 10 instead of 0