Tentamen NDG011 Systemarkitektprogrammet. 40 poäng

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1 Objektorienterad programmering i Java Provmoment: Ladokkod: Tentamen ges för: Tentamen NDG011 Systemarkitektprogrammet 7,5 högskolepoäng Tentamensdatum: Tid: 09:00 13:00 Hjälpmedel: Inga hjälpmedel Totalt antal poäng på tentamen: För att få respektive betyg krävs: G=20 VG=30 40 poäng Allmänna anvisningar: Tentan har en teoretisk och en praktisk del. Fyll i ditt namn, personnummer och dina svar på svarsblanketten på nästa sida. Kontot för den praktiska delen lämnas ut efter att svarsblanketten lämnats in till en tentamensvakt. Notera att frågor där alternativen inleds med alternativen inleds med kan 0 till alla alternative vara korrekta. endast har ett korrekt alternativ. Om Spara alla filer på F: om inte annat specifikt anges. Stäng ner samtliga applikationer och logga ut (via ikon) när du är klar med tentamen. Vid olösliga problem med datorkonto, ta ett nytt och lämna in även detta i tentamensmappen. Den praktiska delen rättas endast om minst 50% av svaren på den teoretiska delen är körrekta. Rättningstiden är som längst tre veckor Viktigt! Glöm inte att skriva namn på alla blad du lämnar in. Lycka till! Ansvarig lärare: Rikard König Telefonnummer:

2 Namn: (Ifylles av student) Personnummer: (Ifylles av student) Svarsblankett A B C D E

3 Theory 1. Java was developed by. A. Sun Microsystems B. Microsoft C. Oracle D. IBM E. Cisco Systems 2. Which of the following statements are true? A. Multiple constructors can be defined in a class. B. Constructors do not have a return type, not even void. C. Constructors must have the same name as the class itself. D. Constructors are invoked using the new operator when an object is created. 3. Which of the following alternatives is not a GRASP pattern A. Low coupling B. High Cohesion C. Indirection D. Adapter 4. Which of the following statements are true? A. Information Expert regards which classes that should exist. B. Pure fabrication regards which classes that are allowed in an application. C. Creator regards how an object should be created. D. GRASP stands for General Relation Assignment Specification Pattern

4 5. Which of the following statements are true? A. A method can be overloaded in the same class. B. A method can be overridden in the same class. C. If a method overloads another method, these two methods must have the same signature. D. If a method overrides another method, these two methods must have the same signature. E. A method in a subclass can overload a method in the superclass. 6. Which component cannot be added to a container? A. JPanel B. JButton C. JFrame D. JComponent 7. You should override the method to draw things on a Swing component. A. repaint() B. update() C. paintcomponent() D. init()

5 8. An instance of are unchecked exceptions. A. RuntimeException B. Exception C. Error D. Throwable E. NumberFormatException 9. Which of the following statements regarding abstract methods are true? A. Abstract classes have constructors. B. A class that contains abstract methods must be abstract. C. It is possible to declare an abstract class that contains no abstract methods. D. An abstract method cannot be contained in a nonabstract class. E. A data field can be declared abstract. 10. Every event object has the method. A. getsource() B. getactioncommand() C. gettimestamp() D. getwhen() E. getkeychar()

6 11. Which of the following statements are true? A. Inner classes can make programs simple and concise. B. An inner class can be declared public or private subject to the same visibility rules applied to a member of the class. C. An inner class can be declared static. A static inner class can be accessed using the outer class name. A static inner class cannot access nonstatic members of the outer class. D. An inner class supports the work of its containing outer class and is compiled into a class named OuterClassName$InnerClassName.class. 12. Which of the following is true? A. The Applet class is in javax.swing package. B. The JApplet class is in javax.swing package. C. Applet is a subclass of JApplet. D. JApplet is a subclass of Applet. 13. If your applet does not have the init() method, which of the following will happen? A. Your program will not compile. B. Your program will compile, but not execute. C. You must have a main method. D. Your program will run just fine since the init() method is defined in the Applet class.

7 14. The Loan class given in the example does not implement java.io.serializable. Analyze the following code. public class Foo implements java.io.serializable { private int v1; private static double v2; private Loan v3 = new Loan(); } A. An instance of Foo can be serialized because Foo implements Serializable. B. An instance of Foo cannot be serialized because Foo contains a non-serializable instance variable v3. C. If you mark v3 as transient, an instance of Foo is serializable. 15. Fill in the code in Comparable c = new Date(); A. <String> B. <?> C. <Date> D. <E> 16. You can use the method to temporarily release time for other threads. A. sleep(long milliseconds) B. yield() C. stop() D. suspend() 17. To obtain an ObjectInputStream from a socket, use. A. socket.getinputstream() B. socket.getobjectstream() C. socket.getobjectinputstream() D. socket.objectinputstream() D. new ObjectInputStream(socket.getInputStream());

8 18. RMI is about. A. passing primitive data between a server and a client B. passing objects between a server and a client C. accessing remote objects and invoking methods from remote objects. D. java.lang.cloneable 19. Which of the following statements are true? A. You may load multiple JDBC drivers in a program. B. You may create multiple connections to a database. C. You may create multiple statements from one connection. D. You can send queries and update statements through a Statement object. 20. Suppose that your program accesses MySQL or Oracle database. Which of the following statements are true? A. If the driver for MySQL and Oracle are not in the classpath, the program will have a syntax error. B. If the driver for MySQL and Oracle are not in the classpath, the program will have a runtime error, indicating that the driver class cannot be loaded. C. If the database is not available, the program will have a syntax error. D. If the database is not available, the program will have a runtime error, when attempting to create a Connection object.

9 Practical assignments 21. The Company Eboda AB has given you the task of creating the domain layer for their hot new drawing application Pohsotohp 6SC. Two of the new really hyped features are the ability to change size of shapes and canvases and to calculate the area of everything, even a whole drawing. However, note that a drawing is not a canvas and a canvas is not a shape even if they may have some common behavior. Polymorphism is a high priority of Ebodas board and should hence be a guiding star for the design of the application. Ebodas CEO Unatnahs Neyaran, who once himself studied object-oriented programming at the University of Borås (HB), has done some initial analysis and concluded that the classes listed below should be implemented. However, it was over ten years since Unatnahs Neyaran studied at HB so he has explicitly pointed out that it is very possible that additional classes and interfaces may be needed to get a really nice object orientation. However, no extra functionality (like a menu system) needs to be implemented and you should not add more functionality to the classes listed below. o Drawing May contain a number of objects that can calculate its own area, e.g. both shapes and canvases can be added to a drawing. Calculates its area as the sum of the area of all its objects. o Canvas Contains a number of shapes. Changes size by changing the size of all its shapes. Calculates its area as the sum of the area of all its shapes o Circle Has a color which is set at creation and cannot be changed. Has a radius which is set at creation. Changes size by changing radius. Calculates its area as radius^2 * pi. o Triangle Has a color which is set at creation and cannot be changed. Have a width and a height which is set at creation. Changes size by changing width and height. Calculates its area as width*height/2. (10p)

10 22. Your task is to create a simple mediator system consisting of two negotiators and the mediator. In each turn both negotiators submit a numeric value to the mediator. The mediator returns agreed if the values are the same. If negotiator x have submitted a higher value than negotiator y, then the mediator returns highest bid to negotiator x and too low to negotiator y. A negotiator may withdraw from the negotiation by submitting a negative value. Then the mediator should inform the other negotiator that there will be no deal and end the session. The mediator should be able to handle sessions between multiple pairs of negotiators at the same time. The negotiators should only be able to connect to the mediator. When two negotiators have connected to the mediator a session should be created which handles the session until the negotiation is agreed upon. Solutions with a mediator that can handle only one session (or one session at a time) can at most get 6 points. The input and output may be handled via the console. The negotiators should be notified after each turn of the mediator s response together with their own value. To get full points, you must define the protocol for the interaction from both negotiators and the mediator. Obviously, your solution must also follow the protocol you have specified. A solution without a protocol can get maximum 8 points. The protocol should be defined in comments in the header of the mediator class. (10p)