clone() Method Without super.clone()

Description

All implementations of clone() should obtain the new object by calling super.clone(). If a class does not follow this convention, a subclass's clone() method will return an object of the wrong type.

Demonstrations

The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

The following two classes demonstrate a bug introduced by not calling super.clone(). Because of the way Kibitzer implements clone(), FancyKibitzer's clone method will return an object of type Kibitzer instead of FancyKibitzer.

public class Kibitzer {

  public Object clone() throws CloneNotSupportedException {


    Object returnMe = new Kibitzer();
    ...

  }

}

public class FancyKibitzer extends Kibitzer{

  public Object clone() throws CloneNotSupportedException {


    Object returnMe = super.clone();
    ...

  }

}

See Also