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注：里面部分标点符号出错，应该不影响会做题的人(这是第一部分)。 1 Given: 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. 0 B. 1 C. 14 D. ?15 E. An error at line 3 causes compilation to fail. F. An error at line 4 causes compilation to fail. 2www Given: 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)) 3 Exhibit : 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. 4www Given 1. Public class test ( 2. Public static void main (String args[]) ( 3. System.out.printIn (6 ^ 3); 4. ) 5. ) What is the output? 5 5java方法参数传递，传的是对象的引用。www Given: 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. 6 Exhibit: 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 textBufferString = new StringBuffer (“java”); 13. 14. stringReplace (textString); 15. BufferReplace (textBufferString); 16. 17. System.out.println (textString + textBuffer); 18. } 19. ) What is the output? javajavac 7www Exhibit: 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. 8 Given: 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) { } 9 Given: 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;) 10 Given: 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 here 8. ) 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;} |
