Line 5
Line 6
Line 7
Line 8
Line 9
Line 10
第1题:
1. class Test { 2. private Demo d; 3. void start() { 4. d = new Demo(); 5. this.takeDemo(d); 6. } 7. 8. void takeDemo(Demo demo) { 9. demo = null; 10. demo = new Demo(); 11. } 12. } When is the Demo object, created on line 3, eligible for garbage collection?()
第2题:
12. void start() { 13. A a = new A(); 14. B b = new B(); 15. a.s(b); 16. b = null; 17. a = null; 18. System.out.println(“start completed”); 19. } When is the B object, created in line 14, eligible for garbage collection?()
第3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?()
第4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?()
第5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?()
第6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) } }
第7题:
Line 16
Line 17
Line 18
Line 19
第8题:
Line 5
Line 6
Line 7
Line 8
Line 9
Line 10
第9题:
Line 5
Line 6
Line 7
Line 8
Line 9
Line 10
第10题:
The line marked (1).
The line marked (2).
The line marked (3).
The line marked (4).
The line marked (5).
第11题:
Just after line 5.
Just after line 6.
Just after line 7.
Just after line 8(that is, as the method returns).
第12题:
After line 16.
After line 17.
After line 18 (when the methods ends).
There is no way to be absolutely certain.
The object is NOT eligible for garbage collection.
第13题:
10. public Object m() { 11. Object o = new Float(3.14F); 12. Object [] oa = new Object[1]; 13. oa[0] = o; 14. o = null; 15. return oa[0]; 16. } When is the Float object, created in line 11, eligible for garbage collection?()
第14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?()
第15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?()
第16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?()
第17题:
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?()
第18题:
Just after line 13.
Just after line 14.
Never in this method.
Just after line 15 (that is, as the method returns).
第19题:
Line5
Line6
Line7
Line8
Line9
Line10
第20题:
line 3
line 6
line 7
line 8
line 10
第21题:
After line 5.
After line 9.
After the start() method completes.
When the takeDemo() method completes.
When the instance running this code is made eligible for garbage collection.
第22题:
Just after line 5.
Just after line 6.
Just after line 7.
Just after line 8(that is, as the method returns).
第23题:
Just after line 5
Just after line 6
Just after line 7 (that is, as the method returns)
Never in this method.
第24题:
Just after line 5
Just after line 6
Just after line 7 (that is, as the method returns)
Never in this method.