Create the classes:

package p1;
import p2.*;
public class A {
  public long m(){
    return new B().k(2);
  }
}
package p2;
import p1.*;
public class B extends A {
  private long k(  int a){
    return 2;
  }
  public long k(  long a){
    return 1;
  }
  public long test(){
    return m();
  }
}

apply the push down method refactoring to m 

package p1;
import p2.*;
public class A {
}
package p2;
import p1.*;
public class B extends A {
  public long m(){
    return new B().k(2);
  }
  private long k(  int a){
    return 2;
  }
  public long k(  long a){
    return 1;
  }
  public long test(){
    return m();
  }
}

The transformation changes behavior. After the transformation the test method returns 2 instead of 1