玻璃杯中的花生壳--scjp模拟试题（二）

[java]scjp模拟试题（二）

[ 2006/8/11 11:24:14 | By: 玻璃杯中的花生壳 ]

Question No: 1 public class test (2. public static void main (String args[]) {3. int i = 0xFFFFFFF1;4. int j = ~i;5.6. }7. )What is the decimal value of j at line 5?A. 0B. 1C. 14D. –15E. An error at line 3 causes compilation to fail.F. An error at line 4 causes compilation to fail.答案: C Question No: 2Given:Integer i = new Integer (42);Long 1 = new Long (42);Double d = new Double (42.0);Which two expressions evaluate to True? (Choose Two)A. (i ==1)B. (i == d)C. (d == 1)D. (i.equals (d))E. (d.equals (i))F. (i.equals (42))答案: D, E Question No: 3Exhibit :1. public class test (2. private static int j = 0;3.4. private static boolean methodB(int k) (5. j += k;6. return true;6. )7.8. public static void methodA(int i) {9. boolean b:10. b = i < 10 | methodB (4);11. b = i < 10 || methodB (8);12. }13.14. public static void main (String args[] ) (15. methodA (0);16. system.out.printIn(j);17. )18. )What is the result?A. The program prints “0”B. The program prints “4”C. The program prints “8”D. The program prints “12”E. The code does not complete.答案: B Question No: 4Given1. Public class test (2. Public static void main (String args[]) (3. System.out.printIn (6 ^ 3);4. )5. )What is the output?答案: 5 Question No: 5Given:1. public class Foo {2. public static void main (String [] args) {3. StringBuffer a = new StringBuffer (“A”);4. StringBuffer b = new StringBuffer (“B”);5. operate (a,b);6. system.out.printIn{a + “,” +b};7. }8. static void operate (StringBuffer x, StringBuffer y) {9. x.append {y};10. y = x;11. }12. }What is the result?A. The code compiles and prints “A,B”.B. The code compiles and prints “A,A”.C. The code compiles and prints “B,B”.D. The code compiles and prints “AB,B”.E. The code compiles and prints “AB,AB”.F. The code does not compile because “+” cannot be overloaded for StringBuffer.答案: DQuestion No: 6Exhibit:1. Public class test (2. Public static void stringReplace (String text) (3. Text = text.replace (‘j’ , ‘i’);4. )5.6. public static void bufferReplace (StringBuffer text) (7. text = text.append (“C”)8. )9.10. public static void main (String args[]) (11. String textString = new String (“java”);12. StringBuffer text BufferString = new StringBuffer (“java”);13.14. stringReplace (textString);15. BufferReplace (textBuffer);16.17. System.out.printIn (textString + textBuffer);18. )19. )What is the output?答案: JAVAJAVA Question No: 7Exhibit:1. public class test {2. public static void add3 (Integer i) }3. int val = i.intValue ( );4. val += 3;5. i = new Integer (val);6. )7.8. public static void main (String args [ ] ) {9. Integer i = new Integer (0);10. add3 (i);11. system.out.printIn (i.intValue ( ) );12. }13. )What is the result?A. Compilation will fail.B. The program prints “0”.C. The program prints “3”.D. Compilation will succeed but an exception will be thrown at line 3.答案: B Question No: 8Given:1. public class ConstOver {2. public ConstOver (int x, int y, int z) {3. }4. }Which two overload the ConstOver constructor? (Choose Two)A. ConstOver ( ) { }B. Protected int ConstOver ( ) { }C. Private ConstOver (int z, int y, byte x) { }D. Public Object ConstOver (int x, int y, int z) { }E. Public void ConstOver (byte x, byte y, byte z) { }答案: A, C Question No: 9Given:1. public class MethodOver {2. public void setVar (int a, int b, float c) {3. }4. }Which two overload the setVar method? (Choose Two)A. Private void setVar (int a, float c, int b) { }B. Protected void setVar (int a, int b, float c) { }C. Public int setVar (int a, float c, int b) (return a;)D. Public int setVar (int a, int b, float c) (return a;)E. Protected float setVar (int a, int b, float c) (return c;)答案: A, C Question No: 10Given:1. class BaseClass {2. Private float x = 1.0f ;3. protected float getVar ( ) ( return x;)4. }5. class Subclass extends BaseClass (6. private float x = 2.0f;7. //insert code here8. )Which two are valid examples of method overriding? (Choose Two)A. Float getVar ( ) { return x;}B. Public float getVar ( ) { return x;}C. Float double getVar ( ) { return x;}D. Public float getVar ( ) { return x;}E. Public float getVar (float f ) { return f;}答案: B, D Question No: 11Which two demonstrate an “is a” relationship? (Choose Two)A. public interface Person { }public class Employee extends Person { }B. public interface Shape { }public class Employee extends Shape { }C. public interface Color { }public class Employee extends Color { }D. public class Species { }public class Animal (private Species species;)E. interface Component { }Class Container implements Component (Private Component[ ] children;)答案: D, E Question No: 12Which statement is true?A. An anonymous inner class may be declared as final.B. An anonymous inner class can be declared as private.C. An anonymous inner class can implement multiple interfaces.D. An anonymous inner class can access final variables in any enclosing scope.E. Construction of an instance of a static inner class requires an instance of the enclosing outer class.答案: DQuestion No 13Given:1. package foo;2.3. public class Outer (4. public static class Inner (5. )6. )Which statement is true?A. An instance of the Inner class can be constructed with “new Outer.Inner ()”B. An instance of the inner class cannot be constructed outside of package foo.C. An instance of the inner class can only be constructed from within the outer class.D. From within the package bar, an instance of the inner class can be constructed with “new inner()”答案: A Question No 14Exhibit:1. public class enclosingone (2. public class insideone{}3. )4. public class inertest(5. public static void main (string[]args)(6. enclosingone eo= new enclosingone ();7. //insert code here8. )9. )Which statement at line 7 constructs an instance of the inner class?A. InsideOnew ei= eo.new InsideOn();B. Eo.InsideOne ei = eo.new InsideOne();C. InsideOne ei = EnclosingOne.new InsideOne();D. EnclosingOne.InsideOne ei = eo.new InsideOne();答案: D Question No 15Exhibit:1. interface foo {2. int k = 0;3. }4.5. public class test implements Foo (6. public static void main(String args[]) (7. int i;8. Test test = new test ();9. i= test.k;10.i= Test.k;11.i= Foo.k;12.)13.)14.What is the result?A. Compilation succeeds.B. An error at line 2 causes compilation to fail.C. An error at line 9 causes compilation to fail.D. An error at line 10 causes compilation to fail.E. An error at line 11 causes compilation to fail.答案: A Question No 16Given:1. //point X2. public class foo (3. public static void main (String[]args) throws Exception {4. printWriter out = new PrintWriter (new5. java.io.outputStreamWriter (System.out), true;6. out.printIn(“Hello”);7. )8. }Which statement at PointX on line 1 allows this code to compile and run?A. Import java.io.PrintWriter;B. Include java.io.PrintWriter;C. Import java.io.OutputStreamWriter;D. Include java.io.OutputStreamWriter;E. No statement is needed.答案: A Question No 17Which two statements are reserved words in Java? (Choose Two)A. RunB. ImportC. DefaultD. Implement答案: B, C Question No 18Which three are valid declarations of a float? (Choose Three)A. Float foo = -1;B. Float foo = 1.0;C. Float foo = 42e1;D. Float foo = 2.02f;E. Float foo = 3.03d;F. Float foo = 0x0123;答案: A, D, F Question No 19 Leading the way in IT testing and certification tools, www.testking.comQuestion No 19Given:8. int index = 1;9. boolean[] test = new Boolean[3];10. boolean foo= test [index];What is the result?A. Foo has the value of 0.B. Foo has the value of null.C. Foo has the value of true.D. Foo has the value of false.E. An exception is thrown.F. The code will not compile.答案: DQuestion No 20Given:1. public class test(2. public static void main(string[]args){3. string foo = args [1];4. string foo = args [2];5. string foo = args [3];6. }7. )And command line invocation:Java Test red green blueWhat is the result?A. Baz has the value of “”B. Baz has the value of nullC. Baz has the value of “red”D. Baz has the value of “blue”E. Bax has the value of “green”F. The code does not compile.G. The program throws an exception.答案: GQuestion No 21Given:8. int index = 1;9. int [] foo = new int [3];10.int bar = foo [index];11.int baz = bar + index;What is the result?A. Baz has the value of 0B. Baz has the value of 1C. Baz has the value of 2D. An exception is thrown.E. The code will not compile.答案: B Question No 22Given:1. public class foo {2. public static void main (String[]args) {3. String s;4. system.out.printIn (“s=” + s);5. }6. }What is the result?A. The code compiles and “s=” is printed.B. The code compiles and “s=null” is printed.C. The code does not compile because string s is not initialized.D. The code does not compile because string s cannot be referenced.E. The code compiles, but a NullPointerException is thrown when toString is called.答案: C Question No 23Which will declare a method that forces a subclass to implement it?A. Public double methoda();B. Static void methoda (double d1) {}C. Public native double methoda();D. Abstract public void methoda();E. Protected void methoda (double d1){}答案: D Question No 24You want subclasses in any package to have access to members of a superclass. Which is the mostrestrictive access modifier that will accomplish this objective?A. PublicB. PrivateC. ProtectedD. TransientE. No access modifier is qualified答案: C Question No 25Given:1. abstract class abstrctIt {2. abstract float getFloat ();3. }4. public class AbstractTest extends AbstractIt {5. private float f1= 1.0f;6. private float getFloat () {return f1;}7. }What is the result?A. Compilation is successful.B. An error on line 6 causes a runtime failure.C. An error at line 6 causes compilation to fail.D. An error at line 2 causes compilation to fail.答案: C Question No 26Exhibit:1. public class test(2. public int aMethod()[3. static int i=0;4. i++;5. return I;6. ]7. public static void main (String args[]){8. test test = new test();9. test.aMethod();10.int j = test.aMethod();11.System.out.printIn(j);12.}13.)What is the result?A. Compilation will fail.B. Compilation will succeed and the program will print “0”C. Compilation will succeed and the program will print “1”D. Compilation will succeed and the program will print “2”答案: D Question No 27Given:1. class super {2. public float getNum() {return 3.0f;}3. }4.5. public class Sub extends Super {6.7. }Which method, placed at line 6, will cause a compiler error?A. Public float getNum() {return 4.0f; }B. Public void getNum () { }C. Public void getNum (double d) { }D. Public double getNum (float d) {retrun 4.0f; }答案: B Question No 28Which declaration prevents creating a subclass of an outer class?A. Static class FooBar{}B. Private class FooBar{}C. Abstract public class FooBar{}D. Final public class FooBar{}E. Final abstract class FooBar{}答案: D Question No 29Given:1. byte [] arry1, array2[];2. byte array3 [][];3. byte[][] array4;If each array has been initialized, which statement will cause a compiler error?A. Array2 = array1;B. Array2 = array3;C. Array2 = array4;D. Both A and BE. Both A and CF. Both B and C答案: F Question No 30Exhibit:1. class super (2. public int I = 0;3.4. public super (string text) (5. I = 16. )7. )8.9. public class sub extends super (10. public sub (string text) (11. i= 212. )13.14. public static void main (straing args[]) (15. sub sub = new sub (“Hello”);16. system.out. PrintIn(sub.i);17. )18. )What is the result?A. Compilation will fail.B. Compilation will succeed and the program will print “0”C. Compilation will succeed and the program will print “1”D. Compilation will succeed and the program will print “2”答案: AQuestion No 31Given:1. public class returnIt (2. returnType methodA(byte x, double y) (3. return (short) x/y * 2;4. )5. )What is the valid returnType for methodA in line 2?A. IntB. ByteC. LongD. ShortE. FloatF. Double答案: F Question No 32Given the ActionEvent, which method allows you to identify the affected component?A. GetClass.B. GetTarget.C. GetSource.D. GetComponent.E. GetTargetComponent.答案: C Question No 33Which is a method of the MouseMotionListener interface?A. Public void mouseMoved(MouseEvent)B. Public boolean mouseMoved(MouseEvent)C. Public void mouseMoved(MouseMotionEvent)D. Public boolean MouseMoved(MouseMotionEvent)E. Public boolean mouseMoved(MouseMotionEvent)答案: A Question No 34Exhibit:1. import java.awt*;2.3. public class X extends Frame (4. public static void main(string []args) (5. X x = new X ();6. X.pack();7. x.setVisible(true);8. )9.10. public X () (11. setlayout (new GridLayout (2,2));12.13. Panel p1 = new panel();14. Add(p1);15. Button b1= new Button (“One”);16. P1.add(b1);17.18. Panel p2 = new panel();19. Add(p2);20. Button b2= new Button (“Two”);21. P2.add(b2);22.23. Button b3= new Button (“Three”);24. add(b3);25.26. Button b4= new Button (“Four”);27. add(b4);28. )29. )Which two statements are true? (Choose Two)A. All the buttons change height if the frame height is resized.B. All the buttons change width if the Frame width is resized.C. The size of the button labeled “One” is constant even if the Frame is resized.D. Both width and height of the button labeled “Three” might change if the Frame is resized.答案: C, D Question No 35You are assigned the task of building a panel containing a TextArea at the top, a label directly below it,and a button directly below the label. If the three components are added directly to the panel. Whichlayout manager can the panel use to ensure that the TextArea absorbs all of the free vertical space whenthe panel is resized?A. GridLayout.B. CardLayout.C. FlowLayout.D. BorderLayout.E. GridBagLayout.答案: E Question No 36Which gets the name of the parent directory file “file.txt”?A. String name= File.getParentName(“file.txt”);B. String name= (new File(“file.txt”)).getParent();C. String name = (new File(“file.txt”)).getParentName();D. String name= (new File(“file.txt”)).getParentFile();E. Directory dir=(new File (“file.txt”)).getParentDir();String name= dir.getName();答案: B Question No 37Which can be used to encode charS for output?A. Java.io.OutputStream.B. Java.io.OutputStreamWriter.C. Java.io.EncodeOutputStream.D. Java.io.EncodeWriter.E. Java.io.BufferedOutputStream.答案: BQuestion No 38The file “file.txt” exists on the file system and contsins ASCII text.Given:38. try {39. File f = new File(“file.txt”);40. OutputStream out = new FileOutputStream(f, true);41. }42. catch (IOException) {}What is the result?A. The code does not compile.B. The code runs and no change is made to the file.C. The code runs and sets the length of the file to 0.D. An exception is thrown because the file is not closed.E. The code runs and deletes the file from the file system.答案: A Question No 39Which constructs a DataOutputStream?A. New dataOutputStream(“out.txt”);B. New dataOutputStream(new file(“out.txt”));C. New dataOutputStream(new writer(“out.txt”));D. New dataOutputStream(new FileWriter(“out.txt”));E. New dataOutputStream(new OutputStream(“out.txt”));F. New dataOutputStream(new FileOutputStream(“out.txt”));答案: F Question No 40What writes the text “” to the end of the file “file.txt”?A. OutputStream out= new FileOutputStream (“file.txt”);Out.writeBytes (“/n”);B. OutputStream os= new FileOutputStream (“file.txt”, true);DataOutputStream out = new DataOutputStream(os);out.writeBytes (“/n”);C. OutputStream os= new FileOutputStream (“file.txt”);DataOutputStream out = new DataOutputStream(os);out.writeBytes (“/n”);D. OutputStream os= new OutputStream (“file.txt”, true);DataOutputStream out = new DataOutputStream(os);out.writeBytes (“/n”);答案: B Question No 41Given:1. public class X (2. public object m () {3. object o = new float (3.14F);4. object [] oa = new object [1];5. oa[0]= o;6. o = null;7. return oa[0];8. }9. )When is the float object created in line 3, eligible for garbage collection?A. Just after line 5B. Just after line 6C. Just after line 7 (that is, as the method returns)D. Never in this method.答案: DQuestion No 42Given:3. string foo = “ABCDE”;4. foo.substring(3);5. foo.concat(“XYZ”);6.Type the value of foo at line 6.答案: ABCDEQuestion No 43Which method is an appropriate way to determine the cosine of 42 degrees?A. Double d = Math.cos(42);B. Double d = Math.cosine(42);C. Double d = Math.cos(Math.toRadians(42));D. Double d = Math.cos(Math.toDegrees(42));E. Double d = Math.cosine(Math.toRadians(42));答案: C Question No 44You need to store elements in a collection that guarantees that no duplicates are stored and all elementscan be accessed in natural order. Which interface provides that capability?A. Java.util.Map.B. Java.util.Set.C. Java.util.List.D. Java.util.StoredSet.E. Java.util.StoredMap.F. Java.util.Collection.答案: D Question No 45Which statement is true for the class java.util.HashSet?A. The elements in the collection are ordered.B. The collection is guaranteed to be immutable.C. The elements in the collection are guaranteed to be unique.D. The elements in the collection are accessed using a unique key.E. The elements in the collections are guaranteed to be synchronized.答案: C Question No 46Given:1. public class IfTest (2. public static void main(string[]args) {3. int x = 3;4. int y = 1;5. if (x = y)6. system.out.printIn(“Not equal”);7. else8. system.out.printIn(“Equal”);9. }10. )What is the result?A. The output is “Equal”B. The output in “Not Equal”C. An error at line 5 causes compilation to fall.D. The program executes but does not print a message.答案: C Question No 47Exhibit:1. public class test (2. public static void main(string args[]) {3. int 1= 0;4. while (i) {5. if (i==4) {6. break;7. }8. ++i;9. }10.11. }12. )What is the value of i at line 10?A. 0B. 3C. 4D. 5E. The code will not compile.答案: E Question No 48Given:3. int i= 1, j= 10 ;4. do (5. if (i++> --j) continue;6. ) while (i<5);After execution, what are the values for I and j?A. i = 6 and j= 5B. i = 5 and j= 5C. i = 6 and j= 4D. i = 5 and j= 6E. i = 6 and j= 6答案: D Question No 49Given:1. switch (i) {2. default:310-025Leading the way in IT testing and certification tools, www.testking.com- 27 -3. System.out.printIn(“Hello”);4. }What are the two acceptable types for the variable i? (Choose Two)A. CharB. ByteC. FloatD. DoubleE. Object答案: A, B Question No 50Given:1. public class foo {2. public static void main (string[]args)3. try {return;}4. finally {system.out.printIn(“Finally”);}5. }6. }What is the result?A. The program runs and prints nothing.B. The program runs and prints “Finally”C. The code compiles, but an exception is thrown at runtime.D. The code will not compile because the catch block is missing.答案: B Question No 51 51． Given the following incomplete method: 1) public void method(){ 2} 3} if (someTestFails()){ 4} 5} } 6} 7} } You want to make this method throw an IOException if,and only if,the method someTestFails() returns a value of true. Which changes achieve this? A. Add at line 2:IOException e; B. Add at line 4:throw e; C. Add at line 4:throw new IOException(); D. Add at line 6:throw new IOException(); E. Modify the method declaration to indicate that an object of type Exception might be thrown. 答案: C、E Question No 5252． Given the following definition: String s = null; Which code fragments cause an object of type NullPointerException to be thrown? A. if((s!=null)&(s.length()>0)) B. if((s!=null)&&(s.length()>0)) C. if((s==null)|(s.length()==0)) D. if((s==null)||(s.length()==0)) 答案: A、C Question No 5353． The following is a program 1) class Exsuper{ 2} String name; 3} String nick_name; 4} 5} public ExSuper(String s,String t){ 6} name = s; 7} nick_name = t; 8} } 9} 10} public string toString(){ 11} return name; 12} } 13} } 14) 15) public class Example extends ExSuper{ 16} 17} public Example(String s,String t){ 18} super(s,t); 19} } 20} 21} public String to String(){ 22} return name +”a.k.a”+nick_name; 23} } 24} 25} public static void main(String args[]){ 26} ExSuper a = new ExSuper(“First”,”1st”); 27} ExSuper b = new Example(“Second”,”2nd”); 28} 29} System.out.println(“a is”+a.toString()); 30} System.out.println(“b is”+b.toString()); 31} } 32} } What happens when the user attempts to compile and run this program? ` A. A Compiler error occurs at line 21 B. An object of type ClassCastException is thrown at line 27 C.The following output: a is First b is second D. The following output: a is First b is Secong a.k.a 2nd F. The following output: a is First a.k.a 1st b is Second a.k.a 2nd 答案:D Question No 5454． Which statements are true about Listeners? A. At most one listener can be added to any simple Component. B. The return value from a listener is used to control the invocation of other listener C. If multiple listeners are added to a single component, they must all be made friends to each other D. If multiple listeners are added to single component, the order of invocation of the listener is not specified. E. In the AWT, listener methods generally take an argument, which is an instance of some subclass of java.awt.AWTEvent class. 答案: D、E Question No 5555． Given the following class outline: class Example{ private int x; // rest of class body public static void main(String args[]){ //implementation of main mehtod} } Which statement is true? A. x=2 is a valid assignment in the main() method of class Example. B. Changing private int x to int x would make x=2 a valid assignment in the main() method of class Example. C. Changing private int x to public int x would make x=2 a valid assignment in the main() method of class Example. D. Changing private int x to static int x would make x=2 a valid assignment in the main() method of class Example. E. Changing class Example to public class Example would make x=2 a valid assignment in the main() method of class Example. 答案:D Question No 5656． Which statement is true about an inner class? A. It must be anonymous B. It can not implement an interface C. It is only accessible in the enclosing class D. It can access any final variables in any enclosing scope. 答案:D Question No 5757． Which statement is true about the grid bag layout manager? A. The number of rows and columns is fixed when the container is created. B. The number of rows and columns is fixed when the GridBagLayout object is created. C. If a component has a fill value of BOTH, then as the container change size, the component is resized. D. Every component must carry a non-zero weightx and weighty value when it is added to the container E. If a row has a weighty value that is non-zero, then as the container changes height, the row changes height. 答案:C Question No 5858． Which statement are true about writing a class that is to handle the events issued by a user interface component. A. Subclassing an adapter is inappropriate in this case. B. The class should implement some listener interface C. A class can implement multiple listener interfaces if desired. D. A subclass of an AWT component cannot listen to its own events. E. When implements listener interface, a class need only provide those handler methods that it chooses. 答案: B、C Question No 5959．The argument for a class?s main() method is called args, and the class is invoked as follows. java Example cat What would be the effect of trying to access args[0] in the main method? A. The value produced is cat B. The value produced is java C. The value produced is Example D. An object of type NullPointerException is thrown. E. An object of type ArrayIndexOutofBoundsException is thrown. 答案:A Question No 6060． Which best describes the requirements of a fully encapsulated class? A. Mehtods must not be private. B. Variables must not be public. C. The class must be marked final D. Public methods are all marked final. E. Modification of the objects state is only possible using method calls. 答案:E Question No 6161．Which contains objects without ordering, duplication, or any particular lookup/retrieval mechanism? A. Map B. Set C. List D. Collection E. Enumeration 答案:B

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