问题:多选题11. public interface Status { 12. /* insert code here */ int MY_VALUE = 10; 13. } Which three are valid on line 12?()AfinalBstaticCnativeDpublicEprivateFabstractGprotected
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问题:单选题public static Iterator reverse(List list) { Collections.reverse(list); return list.iterator(); } public static void main(String[] args) { List list = new ArrayList(); list.add(” 1”); list.add(”2”); list.add(”3”); for (Object obj: reverse(list)) System.out.print(obj + “,”); } What is the result?()A3,2,1,B1,2,3,CCompilation fails.DThe code runs with no output.EAn exception is thrown at runtime.
问题:单选题10. class Nav{ 11. public enum Direction { NORTH, SOUTH, EAST, WEST } 12. } 13. public class Sprite{ 14. // insert code here 15. } Which code, inserted at line 14, allows the Sprite class to compile?()ADirection d = NORTH;BNav.Direction d = NORTH;CDirection d = Direction.NORTH;DNav.Direction d = Nav.Direction.NORTH;
问题:单选题public class X { public static void main(String [] args) { try { badMethod(); System.out.print(“A”); } catch (Exception ex) { System.out.print(“B”); } finally { System.out.print(“C”); } System.out.print(“D”); } public static void badMethod() {} } What is the result?()AACBBDCACDDABCDECompilation fails.
问题:单选题1. interface TestA { String toString(); } 2. public class Test { 3. public static void main(String[] args) { 4. System.out.println(new TestA() { 5. public String toString() { return “test”; } 6. } 7. } 8. } What is the result?()AtestBnullCAn exception is thrown at runtime.DCompilation fails because of an error in line 1.ECompilation fails because of an error in line 4.FCompilation fails because of an error in line 5.
问题:填空题3. string foo = “ABCDE”; 4. foo.substring(3); 5. foo.concat(“XYZ”); 6. Type the value of foo at line 6.()
问题:单选题Which statement is true?()ACompilation fails because the hashCode method is not overridden.BA HashSet could contain multiple Person objects with the same name.CAll Person objects will have the same hash code because the hashCode method is not overridden.DIf a HashSet contains more than one Person object with name="Fred", then removing another Person, also with name="Fred", will remove them all.
问题:单选题public class X implements Runnable( private int x; private int y; public static void main(Stringargs) X that = new X(); (new Thread(that)).start(); (new Thread(that)).start(); ) public void run() ( for (;;) ( x++; y++; System.out.printIn(“x=” + x + “, y = ” + y); ) ) What is the result?()AErrors at lines 7 and 8 cause compilation to fail.BThe program prints pairs of values for x and y that might not always be the same on the same line (for example, “x=2, y=1”).CThe program prints pairs of values for x and y that are always the same on the same line (for example, “x=1, y=1”. In addition, each value appears twice (for example, “x=1, y=1” followed by “x=1, y=1”).DThe program prints pairs of values for x and y that are always the same on the same line (for example, “x=1, y=1”. In addition, each value appears only for once (for example, “x=1, y=1” followed by “x=2, y=2”).
问题:单选题Which gets the name of the parent directory file “file.txt”?()AString name= File.getParentName(“file.txt”);BString name= (new File(“file.txt”)).getParent();CString name = (new File(“file.txt”)).getParentName();DString name= (new File(“file.txt”)).getParentFile();EDirectory dir=(new File (“file.txt”)).getParentDir(); String name= dir.getName();
问题:单选题When creating a class that associates a set of keys with a set of values, which of these interfaces is most applicable?()A CollectionB SetC SortedSetD Map
问题:单选题public class X { public object m () { object o = new float (3.14F); object oa = new object [1]; oa[0]= o; o = null; oa[0] = null; return o; } } When is the float object created in line 3, eligible for garbage collection?()AJust after line 5.BJust after line 6.CJust after line 7.DJust after line 8(that is, as the method returns).
问题:单选题public class X { public static void main(String [] args) { try { badMethod(); System.out.print(“A”); } catch (RuntimeException ex) { System.out.print(“B”); } catch (Exception ex1) { System.out.print(“C”); } finally { System.out.print(“D”); } System.out.print(“E”); } public static void badMethod() { throw new RuntimeException(); } } What is the result?()ABDBBCDCBDEDBCDEEABCDEFCompilation fails.
问题:多选题Which of these are keywords in Java?()AdefaultBNULLCStringDthrowsElong
问题:单选题//point X public class foo { public static void main (Stringargs) throws Exception { java.io.printWriter out = new java.io.PrintWriter { new java.io.outputStreamWriter (System.out), true; out.printIn(“Hello”); } } } Which statement at PointX on line 1 allows this code to compile and run?()AImport java.io.*;BInclude java.io.*;CImport java.io.PrintWriter;DInclude java.io.PrintWriter;ENo statement is needed.
问题:单选题1. public class ForBar { 2. public static void main(String []args) { 3. int i = 0, j = 5; 4. tp: for (;;) { 5. i ++; 6. for(;;) 7. if(i > --j) break tp; 8. } 9. system.out.printIn(“i = ” + i + “, j = “+ j); 10. } 11. } What is the result?()AThe program runs and prints “i=1, j=0”BThe program runs and prints “i=1, j=4”CThe program runs and prints “i=3, j=4”DThe program runs and prints “i=3, j=0”EAn error at line 4 causes compilation to fail.FAn error at line 7 causes compilation to fail.
问题:单选题int i = 0; while (true) { if(i==4) { break; } ++i; } System.out.println(“i=”+i); What is the result?()Ai = 0Bi = 3Ci = 4Di = 5ECompilation fails.
问题:单选题Which statements, when inserted at the indicated position in the following code, will cause a runtime exception when attempting to run the program?() class A {} class B extends A {} class C extends A {} public class Q3ae4 { public static void main(String args[]) { A x = new A(); B y = new B(); C z = new C(); // insert statement here } }A x = y;B z = x;C y = (B) x;D z = (C) y;E y = (A) y;
问题:多选题Class TestException 1. public class TestException extends Exception { 2. } Class a: 1. public class a { 2. 3. public String sayHello(String name) throws TestException { 4. 5. if(name == null) { 6. throw new TestException(); 7. } 8. 9. return “Hello “+ name; 10. } 11. 12. } A programmer wants to use this code in an application: 45. A a=new A(); 46. System.out.println(a.sayHello(”John”)); Which two are true?()AClass a will not compile.BLine 46 can throw the unchecked exception TestException.CLine 45 can throw the unchecked exception TestException.DLine 46 will compile if the enclosing method throws a TestException.ELine 46 will compile if enclosed in a try block, where TestException is caught.
问题:单选题What will be written to the standard output when the following program is run?() public class Q8499 { public static void main(String args[]) { double d = -2.9; int i = (int) d; i *= (int) Math.ceil(d); i *= (int) Math.abs(d); System.out.println(i); } }A 12B 18C 8D 9E 27
问题:多选题Which declarations will allow a class to be started as a standalone program?()Apublic void main(String args[])Bpublic void static main(String args[])Cpublic static main(String[] argv)Dfinal public static void main(String [] array)Epublic static void main(String args[])