Program: 98865
Project: 98865
Buggy source:
@Override public Classroom getClassroomData(IClassroomID classroomID) throws AuthPelpException {
  ClassroomID classroomId=(ClassroomID)classroomID;
  SubjectID subjectId=classroomId.getSubject();
  Classroom classroom=new Classroom(classroomId);
  try {
    String classroomsString=Get("String_Node_Str");
    log.info("String_Node_Str" + classroomsString);
    GsonBuilder gsonBuilder=new GsonBuilder();
    gsonBuilder.registerTypeAdapter(java.util.Date.class,new DateDeserializer());
    Gson gson=gsonBuilder.create();
    ClassroomList classroomList=gson.fromJson(classroomsString,ClassroomList.class);
    edu.uoc.pelp.engine.campus.UOC.vo.Classroom[] classrooms=classroomList.getClassrooms();
    List<IClassroomID> lista=new ArrayList<IClassroomID>();
    String identificadorAula=null;
    for (    edu.uoc.pelp.engine.campus.UOC.vo.Classroom classroomUOC : classrooms) {
      if (classroomUOC.getFatherId().equals(subjectId.getDomainID())) {
        if (getNumAula(classroomUOC.getCode()) == classroomId.getClassIdx().intValue()) {
          identificadorAula=classroomUOC.getId();
          break;
        }
      }
    }
    if (identificadorAula != null) {
      classroom.setSubjectRef(new Subject(subjectId));
      String classroomStudentsString=Get("String_Node_Str" + identificadorAula + "String_Node_Str");
      log.info("String_Node_Str" + classroomStudentsString);
      gsonBuilder=new GsonBuilder();
      gson=gsonBuilder.create();
      UserList studentList=gson.fromJson(classroomStudentsString,UserList.class);
      User[] users=studentList.getUsers();
      for (      User user : users) {
        classroom.addStudent(new Person(new UserID(user.getNumber())));
      }
      String classroomTeachersString=Get("String_Node_Str" + identificadorAula + "String_Node_Str");
      log.info("String_Node_Str" + classroomStudentsString);
      gsonBuilder=new GsonBuilder();
      gson=gsonBuilder.create();
      UserList teachersList=gson.fromJson(classroomTeachersString,UserList.class);
      users=teachersList.getUsers();
      for (      User user : users) {
        classroom.addTeacher(new Person(new UserID(user.getNumber())));
      }
    }
  }
 catch (  Exception e) {
    e.printStackTrace();
  }
  return classroom;
}

Fixed version (ground truth):
@Override public Classroom getClassroomData(IClassroomID classroomID) throws AuthPelpException {
  ClassroomID classroomId=(ClassroomID)classroomID;
  SubjectID subjectId=classroomId.getSubject();
  Classroom classroom=new Classroom(classroomId);
  try {
    String classroomsString=Get("String_Node_Str");
    log.info("String_Node_Str" + classroomsString);
    GsonBuilder gsonBuilder=new GsonBuilder();
    gsonBuilder.registerTypeAdapter(java.util.Date.class,new DateDeserializer());
    Gson gson=gsonBuilder.create();
    ClassroomList classroomList=gson.fromJson(classroomsString,ClassroomList.class);
    String identificadorAula=null;
    if (classroomList != null) {
      edu.uoc.pelp.engine.campus.UOC.vo.Classroom[] classrooms=classroomList.getClassrooms();
      List<IClassroomID> lista=new ArrayList<IClassroomID>();
      for (      edu.uoc.pelp.engine.campus.UOC.vo.Classroom classroomUOC : classrooms) {
        if (classroomUOC.getFatherId().equals(subjectId.getDomainID())) {
          if (getNumAula(classroomUOC.getCode()) == classroomId.getClassIdx().intValue()) {
            identificadorAula=classroomUOC.getId();
            break;
          }
        }
      }
    }
    if (identificadorAula != null) {
      classroom.setSubjectRef(getSubjectData(subjectId));
    }
  }
 catch (  Exception e) {
    e.printStackTrace();
  }
  return classroom;
}