Program: 88421
Project: 88421
Buggy source:
public static RedefinableElement redefineAttribute(final Classifier clazz,final RedefinableElement re,final boolean createSpecializedType,final List<RedefinableElement> traveled){
  if (re.isLeaf()) {
    Application.getInstance().getGUILog().log(re.getQualifiedName() + "String_Node_Str");
  }
  if (!clazz.isEditable()) {
    Application.getInstance().getGUILog().log(clazz.getQualifiedName() + "String_Node_Str");
    return null;
  }
  if (clazz instanceof Activity) {
    Activity act=(Activity)clazz;
    RedefinableElement redefinedElement=null;
    for (    final Behavior p : act.getOwnedBehavior()) {
      if (p instanceof RedefinableElement && p.getRedefinedElement().contains(re)) {
        redefinedElement=p;
        break;
      }
    }
    if (redefinedElement == null) {
      redefinedElement=(RedefinableElement)CopyPasting.copyPasteElement(re,act,false);
      if (redefinedElement instanceof Namespace) {
        Collection<?> emptyCollection=new ArrayList<String>();
        ((Namespace)redefinedElement).getOwnedMember().retainAll(emptyCollection);
      }
      redefinedElement.getRedefinedElement().add(re);
      if (createSpecializedType && redefinedElement instanceof Property && redefinedElement instanceof TypedElement&& ((TypedElement)redefinedElement).getType() != null) {
        CreateSpecializedTypeAction.createSpecializedType((Property)redefinedElement,clazz,true,traveled,null,false);
      }
      return redefinedElement;
    }
 else {
      Application.getInstance().getGUILog().log(re.getQualifiedName() + "String_Node_Str" + clazz.getQualifiedName()+ "String_Node_Str");
      return null;
    }
  }
 else {
    Application.getInstance().getGUILog().log(clazz.getQualifiedName() + "String_Node_Str");
    return null;
  }
}

Fixed version (ground truth):
public static RedefinableElement redefineAttribute(final Classifier clazz,final RedefinableElement re,final boolean createSpecializedType,final List<RedefinableElement> traveled){
  if (re.isLeaf()) {
    Application.getInstance().getGUILog().log(re.getQualifiedName() + "String_Node_Str");
  }
  if (!clazz.isEditable()) {
    Application.getInstance().getGUILog().log(clazz.getQualifiedName() + "String_Node_Str");
    return null;
  }
  if (clazz instanceof Activity) {
    Activity act=(Activity)clazz;
    RedefinableElement redefinedElement=null;
    for (    final Behavior p : act.getOwnedBehavior()) {
      if (p instanceof RedefinableElement && p.getRedefinedElement().contains(re)) {
        redefinedElement=p;
        break;
      }
    }
    if (redefinedElement == null) {
      redefinedElement=(RedefinableElement)CopyPasting.copyPasteElement(re,act,false);
      if (redefinedElement instanceof Namespace) {
        Collection<?> emptyCollection=new ArrayList<String>();
        ((Namespace)redefinedElement).getOwnedMember().retainAll(emptyCollection);
      }
      redefinedElement.getRedefinedElement().add(re);
      if (createSpecializedType && redefinedElement instanceof Property && redefinedElement instanceof TypedElement&& ((TypedElement)redefinedElement).getType() != null) {
        CreateSpecializedTypeAction.createSpecializedType((Property)redefinedElement,clazz,traveled,null,false,true);
      }
      return redefinedElement;
    }
 else {
      Application.getInstance().getGUILog().log(re.getQualifiedName() + "String_Node_Str" + clazz.getQualifiedName()+ "String_Node_Str");
      return null;
    }
  }
 else {
    Application.getInstance().getGUILog().log(clazz.getQualifiedName() + "String_Node_Str");
    return null;
  }
}