Exam Procedure

The examination is divided in two parts:

1. Theoretical questions on topics discussed during lectures (weight on the final grade ~15%), described below.

2. The development of a Java program, using the Eclipse IDE (weight on the final grade ~85%).

The final grade will be published on the student portal and it can be rejected.

Theory Questions

The question topics are theoretical Software Engineering and Java language general characteristics.

General knowledge of such topics is sufficient to answer the questions correctly, a mnemonic knowledge of the details is not necessary.

How to answer the questions

The questions are accessible in a text file inside the Eclipse Java project. All question can have zero or more correct answers.

There will be four questions:

• 2 questions on the Java Language
• 2 questions of the remaining topics

Among the proposed options the students are required to select those they deem correct (possibly none).

An example questionnaire with the relative questions is reported below:

1. Which among the following statements are valid for a Java interface?
[ ] A1.1 - An interface can contain regular attributes
[ ] A1.2 - An interface can contain abstract methods
[ ] A1.3 - An interface can contain static methods
[ ] A1.4 - An interface can be empty
[ ] A1.5 - An interface must at least an abstract method

2. What is the purpose of the operator `->`?
[ ] A2.1 - define a conditional expression
[ ] A2.2 - define a reverse assignment
[ ] A2.3 - implement a functional interface
[ ] A2.4 - define *method reference*
[ ] A2.5 - extend a class

3. What method is used by SVN to solve conflicts?
[ ] A3.1 - Lock-Unlock-Modify
[ ] A3.2 - Lock-Modify-Unlock
[ ] A3.3 - Check-out/Check-in
[ ] A3.4 - Check-out/Commit
[ ] A3.5 - Copy-Modify-Merge

4. What is included in the middle section of a UML class?
[ ] A4.1 - Name of the class
[ ] A4.2 - Implementation
[ ] A4.3 - Interface
[ ] A4.4 - Methods
[ ] A4.5 - Attributes

To select an answer place a "X" in the "[ ]" --> "[X]"

Answer Evaluation

The grade for the answers to the theoretical questions is evaluated with the following rules:

• no answer: 0 points
• perfectly correct answers: 1 point
• completely wrong answers: -1 points

Partial answers, or answers including wrong elements, will lead to intermediate grades, evaluated using a formula based on the the accuracy.

Programming part

General rules

The reference programming language is Java 8.

During the exam the access to the following resources is allowed:

• personal repository used during the labs (https://oop.polito.it/svn/OOPLabs/s######/)
• programming examples shown during lectures (https://oop.polito.it/svn/OOP2018/...)
• laboratory exercises and relative solutions (>https://oop.polito.it/svn/OOPLabs/master/>)
• Java API documentation (from a link on desktop or https://oop.polito.it/api/)
• slides presented in lectures (https://oop.polito.it/material/)

The exam must be completed autonomously without any help from other persons. In case of suspected violation of this rule the exam will be cancelled.

To take the exam you must know how to:

• use the Eclipse IDE
• check-out and commit a project in a SVN repository
• write Java programs using all Java features presented during the course

No assistance will be provided on these topics during the exam.

It is required to access the repository and perform the exam from a single device and using a single internet connection; in case of technical problems students are required to notify the teachers as soon as possible.

Personal repositories (previously disabled) are enabled at the same time for all and announced the beginning of the exam.

WARNING Repository credentials are available to students before the exam: they are the same personal repositories used during the labs (whoever is missing their credentials must contact the teachers al least 2 days in advance)

WARNING Since the day before the exam, personal repositories will NOT ne accessible.

Procedure - Lab

• Start your LAIB PC and login using the official Politecnico credentials

• Start Eclipse (Oxygen 2)

  • open the folder Programmi Vari on the desktop,
  • The list of installed programs appears,
  • Double click on Eclipse Oxygen 2 to start Eclipse
  • Select a workspace located in your PC home folder

Procedure - Remote

The programming part is conducted on student’s own PC. During the exam students must be connected to the support VC whose link is sent via email before the exam to all booked students.

Within the support VC:

• all students must keep their webcam turned on

• questions and answers are written on the public chat

• possible correction to the requirements are published on the chat, which has to be checked periodically by the students

• teachers can ask, in any moment, to any student to share their screen to check what they are doing

• Start your Eclipse installation (2020-12)

Common procedure

During Exam

• WAIT for the teacher to announce repositories are online
• Import the project from the SVN repository
• Work on your exam, remembering that:
  • You can find the requisites in the Requirements.html file inside the project (Right-Click, Open With, Web Browser)
  • A minimalistic test is provided to check the program
  • Frequent commits are strongly suggested, typically after implementing each requisite
• You will be warned 10 minutes before the exam end, in order to have enough time to fix errors (if there are any), and to try to execute the example program at least one time.
• Remember to answer the theory questions
• 5 minutes before the exam end you will be asked to submit the project with the following procedure:
  • Select the project (after having saved all files)
  • Right-click on the project and select “Team” and then Commit..
  • Insert a comment (e.g. final lab version), and then click on Ok to confirm the commit

After exam

• Within approximately 24-48 hours from the exam end, you will receive an email containing the results of the acceptance tests, a link to such tests and the due date to deliver the correct version of your program
• Check-out the project from the SVN repository
• Follow the instructions available at http://softeng.polito.it/courses/tutorial/UseTests_it.html to insert and execute the tests on your project.
• Correct the exam in order to pass all the tests, modifying the code as little as possible.
• Commit the correct project version on the SVN repository.
  • Multiple commits are allowed, only the latest will be considered

Evaluation criteria

The evaluation is based on the two versions of the program

• the exam version: the one on the SVN repository at the end of the lab examination
  • in presence of more than one commit, only the last one will be evaluated
  • commits done after the official end of the lab examination will not be evaluated
• the home version: the one on the SVN repository at the due date of the delivery

The grade of the programming examination is based on two parts:

1. the percentage of tests passed by the lab version
2. the inverse of the number of modifications applied at home to the program in order to pass all the tests (i.e. the difference between the home and exam versions)

The program is recompiled with the standard javac compiler running in a linux environment. If the program causes compilation errors the number of passed tests is automatically evaluated as 0 (zero).

The proportion of passed tests is normalized on the basis of the general outcome of the exam. In any case the project committed after exam must pass all tests.

If the home program does not pass all the tests, the exam will not be evaluated, and the student will be considered as retired from the exam.

Eventual correlations between the tests failures will not be considered in any way: it does not matter if more than one test fail due to the same error, only the passed/failed number of tests is considered. Obviously, if fixing a single error allow the program to pass various tests that failed in the lab version, this entails a less modifications (thus leading to an higher value for the second component of the grade)

Recommendations

Given the evaluation criteria, you should abide to the following recommendations:

• Do not change the methods signature (name, return type, parameters and exceptions): such changes will lead to the impossibility of executing the tests, i.e. to their failure.
• Do not implement characteristics not explicitly requested in the exam paper: they are not evaluated, you just lose time.
• Checkout the single project, not all the repository.
• Since commits out of time are not considered, do a “safety” commit some minutes before the exam end.
• Do not insert infinite loops: the tests are interrupted after a timeout, leading to a failure.
• Do not use letters with accents (non ASCII) to avoid errors at compile time
• Do not end a program using System.exit().
• Run the test program at least once.
• Remove spurious import that refer to non-standard classes.

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