Program: 98883
Project: 98883
Buggy source:
@Override public String execute() throws Exception {
  if (bUOC.getUserInformation() != null) {
    listSubjects=bUOC.getUserSubjects();
    if (s_assign != null) {
      String[] infoAssing=s_assign.split("String_Node_Str");
      teacher=bUOC.isTeacher(new UOCSubject(infoAssing[0],infoAssing[2]));
      listClassroms=bUOC.getUserClassrooms(new UOCSubject(infoAssing[0],infoAssing[2]));
    }
    if (s_aula != null && s_aula.length() > 0 && s_assign != null) {
      String[] infoAssing=s_assign.split("String_Node_Str");
      listActivity=bUOC.getSubjectActivities(new UOCSubject(infoAssing[0],infoAssing[2]));
    }
    if (s_aula != null && s_aula.length() > 0 && s_assign != null && s_activ != null && s_activ.length() > 0) {
      Activity objActivity=new Activity();
      for (int j=0; j < listActivity.length; j++) {
        if (listActivity[j].getIndex() == Integer.parseInt(s_activ)) {
          objActivity=listActivity[j];
        }
      }
      String[] infoAssing=s_assign.split("String_Node_Str");
      listDeliverDetails=bUOC.getUserDeliverDetails(new UOCSubject(infoAssing[0],infoAssing[2]),objActivity.getIndex());
    }
    imageURL=bUOC.getUserInformation().getUserPhoto();
    if (imageURL == null)     imageURL="String_Node_Str";
    fullName=bUOC.getUserInformation().getUserFullName();
  }
 else {
    imageURL=null;
    fullName=null;
  }
  String toReturn=SUCCESS;
  if (TAB_PROGRAMMING_ENVIROMENT.equals(activeTab)) {
    toReturn=TAB_PROGRAMMING_ENVIROMENT;
  }
  return toReturn;
}

Fixed version (ground truth):
@Override public String execute() throws Exception {
  if (bUOC.getUserInformation() != null) {
    listSubjects=bUOC.getUserSubjects();
    if (s_assign != null) {
      String[] infoAssing=s_assign.split("String_Node_Str");
      teacher=bUOC.isTeacher(new UOCSubject(infoAssing[0],infoAssing[2]));
      listClassroms=bUOC.getUserClassrooms(new UOCSubject(infoAssing[0],infoAssing[2]));
    }
    if (s_aula != null && s_aula.length() > 0 && s_assign != null) {
      String[] infoAssing=s_assign.split("String_Node_Str");
      listActivity=bUOC.getSubjectActivities(new UOCSubject(infoAssing[0],infoAssing[2]));
    }
    if (s_aula != null && s_aula.length() > 0 && s_assign != null && s_activ != null && s_activ.length() > 0) {
      Activity objActivity=new Activity();
      for (int j=0; j < listActivity.length; j++) {
        if (listActivity[j].getIndex() == Integer.parseInt(s_activ)) {
          objActivity=listActivity[j];
        }
      }
      String[] infoAssing=s_assign.split("String_Node_Str");
      if (teacher) {
        Classroom objClass=null;
        for (int i=0; i < listClassroms.length; i++) {
          if (listClassroms[i].getIndex() == Integer.parseInt(s_aula)) {
            objClass=listClassroms[i];
          }
        }
        bUOC.getAllClassroomDeliverDetails(objActivity,new UOCSubject(infoAssing[0],infoAssing[2]),objClass.getIndex());
      }
 else {
        listDeliverDetails=bUOC.getUserDeliverDetails(new UOCSubject(infoAssing[0],infoAssing[2]),objActivity.getIndex());
      }
    }
    imageURL=bUOC.getUserInformation().getUserPhoto();
    if (imageURL == null)     imageURL="String_Node_Str";
    fullName=bUOC.getUserInformation().getUserFullName();
  }
 else {
    imageURL=null;
    fullName=null;
  }
  String toReturn=SUCCESS;
  if (TAB_PROGRAMMING_ENVIROMENT.equals(activeTab)) {
    toReturn=TAB_PROGRAMMING_ENVIROMENT;
  }
  return toReturn;
}