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1题:
10. class Line { 11. public static class Point { } 12. } 13. 14. class Triangle { 15. // insert code here 16. } Which code, inserted at line 15, creates an instance of the Point class defined in Line?()
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:
11. public static void append(List list) { list.add(”0042”); } 12. public static void main(String[] args) { 13. List
第4题:
11. static classA { 12. void process() throws Exception { throw new Exception(); } 13. } 14. static class B extends A { 15. void process() { System.out.println(”B “); } 16. } 17. public static void main(String[] args) { 18.A a=new B(); 19. a.process(); 20.} What is the result?()
第5题:
Given: 11. static class A { 12. void process() throws Exception { throw new Exception(); } 13. } 14. static class B extends A { 15. void process() { System.out.println("B "); } 16. } 17. public static void main(String[] args) { 18. A a = new B(); 19. a.process(); 20. } What is the result? ()
第6题:
42
0042
An exception is thrown at runtime.
Compilation fails because of an error in line 13.
Compilation fails because of an error in line 14.
第7题:
B
The code runs with no output.
Compilation fails because of an error in line 12.
Compilation fails because of an error in line 15.
Compilation fails because of an error in line 18.
第8题:
Point p = new Point();
Line.Point p = new Line.Point();
The Point class cannot be instatiated at line 15.
Line 1 = new Line() ; 1.Point p = new 1.Point();
第9题:
B
The code runs with no output.
An exception is thrown at runtime.
Compilation fails because of an error in line 15.
Compilation fails because of an error in line 18.
Compilation fails because of an error in line 19.
第10题:
StackOverflowError
NullPointerException
NumberFormatException
IllegalArgumentException
ExceptionlnlnitializerError
第11题:
a.wait();
t.wait();
t.join();
t.yield();
t.notify();
a.notify();
t.interrupt();
第12题:
a2.m2();
((Beta)a2).m2();
((Alpha)a2).m2();
((Gamma)a2).m2();
第13题:
11. static class A { 12. void process() throws Exception { throw new Exception(); } 13. } 14. static class B extends A { 15. void process() { System.out.println(”B”); } 16. } 17. public static void main(String[] args) { 18. new B().process(); 19. } What is the result?()
第14题:
Which two code fragments will execute the method doStuff() in a separate thread?()
第15题:
public class Threads4 { public static void main (String[] args) { new Threads4().go(); } public void go() { Runnable r = new Runnable() { public void run() { System.out.print(”foo”); } }; Thread t = new Thread(r); t.start(); t.start(); } } What is the result?()
第16题:
Given that a static method doIt() in a class Work represents work to be done, what block of code will succeed in starting a new thread that will do the work? CODE BLOCK a: Runnable r = new Runnable() { public void run() { Work.doIt(); } }; Thread t = new Thread(r); t.start(); CODE BLOCK b: Thread t = new Thread() { public void start() { Work.doIt(); } }; t.start(); CODE BLOCK c: Runnable r = new Runnable() { public void run() { Work.doIt(); } }; r.start(); CODE BLOCK d: Thread t = new Thread(new Work()); t.start(); CODE BLOCK e: Runnable t = new Runnable() { public void run() { Work.doIt(); } }; t.run();
第17题:
Which two code fragments will execute the method doStuff() in a separate thread?()
第18题:
Thread.sleep(1);
Thread.sleep(100);
Thread.sleep(1000);
try { Thread.sleep(100); } catch (Exception e) { }
第19题:
Foo { public int bar() { return 1; } }
new Foo { public int bar() { return 1; } }
newFoo() { public int bar(){return 1; } }
new class Foo { public int bar() { return 1; } }
第20题:
Exception
A Exception
A Exception B
A B Exception
Compilation fails because of an error in line 14.
Compilation fails because of an error in line 19.
第21题:
Code block a.
Code block B.
Code block c.
Code block d.
Code block e.
第22题:
Compilation fails because of an error in line 13.
A ClassCastException is thrown at runtime.
1 2 3
Compilation fails because of an error in line 14.
Compilation fails because of an error in line 12.
第23题:
new Thread() { public void run() { doStuff(); } }
new Thread() { public void start() { doStuff(); } }
new Thread() { public void start() { doStuff(); } } .run();
new Thread() { public void run() { doStuff(); } } .start();
new Thread(new Runnable() { public void run() { doStuff(); } } ).run();
new Thread(new Runnable() { public void run() { doStuff(); } }).start();