考题
11.public void genNumbers(){12.ArrayList numbers=new ArrayList();13.for(inti=0;i14.intvalue=i*((int)Math.random());15.IntegerintObj=newInteger(value);16.numbers.add(intObj);17.}18.System.out.println(numbers);19.}Which line of code marks the earliest point that an object referenced by intObj becomes a candidate for garbagec ollection?()A.Line16B.Line17C.Line18D.Line19E.The object is NOT a candidate for garbage collection.
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1.public class GC{2.private Objec to;3.private void doSomethingElse(Object obj){o=obj;}4.public void doSomething(){5.Object o=new Object();6.doSomethingElse(o);7.o=new Object();8.doSomethingElse(null);9.o=null;10.}11.}When the doSomething method is called,after which line does the Object created in line 5 become available for garbage collection?()A.Line5B.Line6C.Line7D.Line8E.Line9F.Line10
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Given:When the doSomething method is called, after which line does the Object created in line 5 become available for garbage collection?()
A.Line 5B.Line 6C.Line 7D.Line 8E.Line 9F.Line 10
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public class X { public object m () { object o = new float (3.14F); object oa = new object [1]; oa[0]= o; o = null; return oa[0]; } } 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.
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11.public void genNumbers(){ 12.ArrayList numbers=new ArrayList(); 13.for(inti=0;i10;i++){ 14.intvalue=i*((int)Math.random()); 15.IntegerintObj=newInteger(value); 16.numbers.add(intObj); 17.} 18.System.out.println(numbers); 19.} Which line of code marks the earliest point that an object referenced by intObj becomes a candidate for garbagec ollection?()A、Line16B、Line17C、Line18D、Line19E、The object is NOT a candidate for garbage collection.
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1. class TestA { 2. TestB b; 3. TestA() { 4. b = new TestB(this); 5. } 6. } 7. class TestB { 8. TestA a; 9. TestB(TestA a) { 10. this.a = a; 11. } 12. } 13. class TestAll { 14. public static void main (String args[]) { 15. new TestAll().makeThings(); 16. // ...code continues on 17. } 18. void makeThings() { 19. TestA test = new TestA(); 20. } 21. } Which two statements are true after line 15, before main completes?()A、 Line 15 causes a stack overflow.B、 An exception is thrown at runtime.C、 The object referenced by a is eligible for garbage collection.D、 The object referenced by b is eligible for garbage collection.E、 The object referenced by a is not eligible for garbage collection.F、 The object referenced by b is not eligible for garbage collection.
考题
1. public class GC { 2. private Object o; 3. private void doSomethingElse(Object obj) { o = obj; } 4. public void doSomething() { 5. Object o = new Object(); 6. doSomethingElse(o); 7. o = new Object(); 8. doSomethingElse(null); 9.o=null; 10. } 11. } When the doSomething method is called, after which line does the Object created in line 5 become available for garbage collection?() A、 Line 5B、 Line 6C、 Line 7D、 Line 8E、 Line 9F、 Line 10
考题
11. public void genNumbers() { 12. ArrayList numbers = new ArrayList(); 13. for (int i=0; i10; i++) { 14. int value = i * ((int) Math.random()); 15. Integer intObj = new Integer(value); 16. numbers.add(intObj); 17. } 18. System.out.println(numbers); 19. } Which line of code marks the earliest point that an object referenced by intObj becomes a candidate for garbage collection?() A、 Line 16B、 Line 17C、 Line 18D、 Line 19E、 The object is NOT a candidate for garbage collection.
考题
1.public class GC{ 2.private Objec to; 3.private void doSomethingElse(Object obj){o=obj;} 4.public void doSomething(){ 5.Object o=new Object(); 6.doSomethingElse(o); 7.o=new Object(); 8.doSomethingElse(null); 9.o=null; 10.} 11.} When the doSomething method is called,after which line does the Object created in line 5 become available for garbage collection?()A、Line5B、Line6C、Line7D、Line8E、Line9F、Line10
考题
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.
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Given the following code fragment: public void create() { Vector myVect; myVect = new Vector(); } Which of the following statements are true?() A、 The declaration on line 2 does not allocate memory space for the variable myVect.B、 The declaration on line 2 allocates memory space for a reference to a Vector object.C、 The statement on line 2 creates an object of class Vector.D、 The statement on line 3 creates an object of class Vector.E、 The statement on line 3 allocates memory space for an object of class Vector.
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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. oa[0] = null; 10. return o; 9. } 10. } When is the float object created in line 3, eligible for garbage collection?() A、 Just after line 5.B、 Just after line 6.C、 Just after line 7.D、 Just after line 8(that is, as the method returns).
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Given the following code: 1) class Parent { 2) private String name; 3) public Parent(){} 4) } 5) public class Child extends Parent { 6) private String department; 7) public Child() {} 8) public String getValue(){ return name; } 9) public static void main(String arg[]) { 10) Parent p = new Parent(); 11) } 12) } Which line will cause error?() A、 line 3B、 line 6C、 line 7D、 line 8E、 line 10
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Given the following code, write a line of code that, when inserted at the indicated location, will make the overriding method in Extension invoke the overridden method in class Base on the current object. class Base { public void print( ) { System.out.println("base"); } } class Extention extends Base { public void print( ) { System.out.println("extension"); // insert line of implementation here } } public class Q294d { public static void main(String args[]) { Extention ext = new Extention( ); ext.print( ); } } Fill in a single line of implementation.()
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Consider the following class: class Test(int i) { void test(int i) { System.out.println(“I am an int.”); } void test(String s) { System.out.println(“I am a string.”); } public static void main(String args) { Test t=new Test(); char ch=“y”; t.test(ch); } } Which of the statements below is true?()A、 Line 5 will not compile, because void methods cannot be overridden.B、 Line 12 will not compile, because there is no version of test() that rakes a charargument.C、 The code will compile but will throw an exception at line 12.D、 The code will compile and produce the following output: I am an int.E、 The code will compile and produce the following output: I am a String.
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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?() A、 Just after line 5.B、 Just after line 6.C、 Just after line 7.D、 Just after line 8(that is, as the method returns).
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1. class Bar { } 1. class Test { 2. Bar doBar() { 3. Bar b = new Bar(); 4. return b; 5. } 6. public static void main (String args[]) { 7. Test t = new Test(); 8. Bar newBar = t.doBar(); 9. System.out.println(“newBar”); 10. newBar = new Bar(); 11. System.out.println(“finishing”); 12. } 13. } At what point is the Bar object, created on line 3, eligible for garbage collection?() A、 After line 8.B、 After line 10.C、 After line 4, when doBar() completes.D、 After line 11, when main() completes.
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11. class Snoochy { 12. Boochybooch; 13. public Snoochy() { booch = new Boochy(this); } 14. } 15. 16. class Boochy { 17. Snoochy snooch; 18. public Boochy(Snoochy s) { snooch = s; } 19. } And the statements: 21. public static void main(String[] args) { 22. Snoochy snoog = new Snoochy(); 23. snoog = null; 24. // more code here 25. } Which statement is true about the objects referenced by snoog, snooch, and booch immediately after line 23 executes?() A、 None of these objects are eligible for garbage collection.B、 Only the object referenced by booch is eligible for garbage collection.C、 Only the object referenced by snoog is eligible for garbage collection.D、 Only the object referenced by snooch is eligible for garbage collection.E、 The objects referenced by snooch and booch are eligible for garbage collection.
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单选题11.public class Counter{ 12.public static void main(String[]args){ 13.int numArgs=/*insert code here*/; 14.} 15.} and the command line:java Counter one fred 42 Which code,inserted at line 13,captures the number of arguments passed into the program?()A
args.countB
args.lengthC
args.count()D
args.length()E
args.getLength()
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单选题Given: Which line of code marks the earliest point that an object referenced by intObj becomes a candidate for garbage collection?()A
Line 16B
Line 17C
Line 18D
Line 19
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单选题Given the following code: 1) class Parent { 2) private String name; 3) public Parent(){} 4) } 5) public class Child extends Parent { 6) private String department; 7) public Child() {} 8) public String getValue(){ return name; } 9) public static void main(String arg[]) { 10) Parent p = new Parent(); 11) } 12) } Which line will cause error?()A
line 3B
line 6C
line 7D
line 8E
line 10
考题
单选题Given: When the doSomething method is called, after which line does the Object created in line 5 become available for garbage collection?()A
Line 5B
Line 6C
Line 7D
Line 8E
Line 9F
Line 10
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单选题Which is the earliest line in the following code after which the object created on the line marked (0) will be a candidate for being garbage collected, assuming no compiler optimizations are done? () public class Q76a9 { static String f() { String a = "hello"; String b = "bye"; // (0) String c = b + "!"; // (1) String d = b; b = a; // (2) d = a; // (3) return c; // (4) } public static void main(String args[]) { String msg = f(); System.out.println(msg); // (5) } }A
The line marked (1).B
The line marked (2).C
The line marked (3).D
The line marked (4).E
The line marked (5).
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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?()A
Just after line 5.B
Just after line 6.C
Just after line 7.D
Just after line 8(that is, as the method returns).
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单选题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. oa[0] = null; 10. return o; 9. } 10. } When is the float object created in line 3, eligible for garbage collection?()A
Just after line 5.B
Just after line 6.C
Just after line 7.D
Just after line 8(that is, as the method returns).
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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; return oa[0]; } } 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.
考题
单选题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.