09级Java技术试题.doc

西安电子科技大学 考试时间 120 分钟试 题题号III总分分数1.考试形式：闭卷；2.考试日期： 年 月 日3.本试卷共 2 大题，满分100分。班级 学号 姓名 任课教师 Note: Write all answers on the answer sheet. Question I: Multiple choices (2*20=40 points)1. Which JDK command is correct to run a Java application in myProgram.java?A. java myProgramB. java myProgram.classC. javac myProgram.javaD. javac myProgram2. Which of the following definitions defines a legal interface?A. interface A abstract void unfinished() B.interface A abstract void unfinished();C.interface A void unfinished();D.public interface A abstract void unfinished();3. Which of the following statements are false?A. A class can only extend one classB. A class can implement more than one interfaceC. An interface can not extend other interfacesD. An interface can extend more than one interface4. Which of the following keywords not belong to the java keywords? A. const B. sizeof C. assert D.volatile 5. Suppose A is an abstract class, B is a concrete subclass of A, and both A and B have a default constructor. Which of the following is not correct?A. A a = new A();B. A a = new B();C. B b = new B();D. B and C are correct6. Analyze the following code, the result is:public class Test public static void main(String args) B b = new B(); b.m(5); b.m(23.0); System.out.println(d is + b.d); class A protected int i; public void m(int i) this.i = i; class B extends A double d; public void m(double d) this.d +=d+i; A. d is 28.0.B. run-time error.C. compile error.D. d is 23.0. 7. What will the following program display when you attempt to compile and run it?public class Test /#1 public static void main(String args) Object a1 = new A(); Object a2 = new A(); A a3 = new A(); A a3 = new A(); String s1=”Hello!”; String s2=”Hello!”; System.out.println(a1.equals(a2); System.out.println(a3.equals(a4); System.out.println(s1.equals(s2); class A int x; public boolean equals(A a) return this.x = a.x; A. B. C. D. truetruefalsefalsefalsetruetruetruetruefalsefalsetrue8. Which one of the following statements is not correct?A. int a20; B. int a=1,2,3,4,5;C. int a; D. int a; a=new int2; a=new int23; a0=new int2; a1=new int3;9. If str is a variable with String type, which one of following can get its length?A. str.length() B. str.lengthC. str.size()D. str.size10. Suppose you have classes Vehicle，Engine, Wheel and Window, and you want to build a Car, which of the following concepts is best suitable for it?A. InheritanceB. Inheritance with Extension C. CompositionD. Composition and Inheritance11. Which of the following statements is not correct?A. Collection c=new TreeSet();B. Collection c=new LinkedList(); C. Collection c=new Stack();D. Collection c=new HashMap();12. Construct an instance of class ArrayList which implementation of the List interface which inherits the Collection interface. Which of the following statements is true where E is String? A. ArrayList myCollection = new String();B. Collection myCollection = new ArrayList();C. ArrayList myCollection = new Collection();D. Collection myCollection = new Collection();13. Which of the following statements creates an instance of Directory on Window for the Directory D:Myfile?A. new File(D:Myfile) B. new File(D:Myfile)C. new File(D:/Myfile) D. new File(D:/Myfile)14. Which of the following expressions must be true if you create a thread using Thread object = new Thread()?A. object instanceof JFrameB. object instanceof FrameC. object instanceof AppletD. object instanceof Runnable15. In which class/collection is the wait() method defined? A. Applet B. RunnableC. Thread D. Object 16. Which of the keywords can makes an object of a class serializable? A.transient B. private C. static D. serializable 17. Analyzing the following code, which of following statements should replace /answer goes hereimport javax.swing.*;public class Display extends JFrame public Display() super(Display); / answer goes here JLabel hello=new JLabel(Hello); JPanel pane=new JPanel(); pane.add(hello); setContentPane(pane); pack(); setVisible(true); public static void main(String args) Display ds =new Display(); A. setSize(300,200);B. setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);C. Display ds=new Display();D. no statement18. Which is the following program result?public class Apublic static void main(String args) String s=if (a=3) a=0;n; char buf=new chars.length(); s.getChars(0,s.length(),buf,0); CharArrayReader in=new CharArrayReader(buf); PushbackReader f=new PushbackReader(in); int c; try while(char)(c=f.read() !=-1) switch(c) case =: if(c=f.read()=) System.out.print(.eq.); else System.out.print(-); f.unread(c); break; default: System.out.print(char)c); break; catch(IOException e)System.out.print(error!); A. if (a-4) a.eq.0 B. if (a.eq.4) a.eq.0C. if (a.eq.4) a-0D. if (a-4) a-019. When an object of a thread invoke sleep method, which state will the thread object enter into?A.new B. block C. runnable D. destroy 20. which is the following program result?public class Demopublic static void main(String args) SuperClass s=new SuperClass(2); SuperClass s1=new SubClass(2,3.4); s.display(); s1.display(); class SuperClass private int