複選題
219 

Which two can be results? (Choose two.) 

(A) java.lang.RuntimeException: Problem 

(B)  

(C) 

(D) 

(E) 

複選題212  Which two code fragments, inserted independently at line 5, will compile without warnings? (Choose two.) (A) public void addStrings(List list){ (B) public void addStrings(List＜String＞ list){ (C) public void addStrings(List＜? super String＞ list){ (D) public void addStrings(List＜? extends String＞ list){

複選題213 Given a class whose instances, when found in a collection of objects, are sorted by using the compareTo() method, which two statements are true? (choose two.) (A) The class implements java.lang.Comparable. (B) The class implements java.util.Comparator. (C) The interface used to implement sorting allows this class to define only one sort sequence. (D) The interface used to implement sorting allows this class to define many different sort sequences.

214 What is the result? (A) Compilation fails. (B) An exception is thrown at runtime. (C) [608, 610, 612, 629] [608, 610] (D) [608, 610, 612, 629] [608, 610, 629] (E) [606, 608, 610, 612, 629] [608, 610] (AB) [606, 608, 610, 612, 629] [608, 610, 629]

215 What is the result? (A) Compilation fails. (B) aAaA aAa AAaa AaA (C) AAaa AaA aAa aAaA (D) AaA AAaa aAaA aAa (E) aAa AaA aAaA AAaa (AB) An exception is thrown at runtime.

220 Which factor or factors  1. It is possible for more than two threads to deadlock at once.  2. The JVM implementation guarantees that multiple threads cannot enter into a deadlocked state.  3. Deadlocked threads release once their sleep() method's sleep duration has expired.  4. Deadlocking can occur only when the wait(), notify() and notifyAll() methods are used incorrectly.  5. It is possible for a single-threaded application to deadlock if synchronized blocks are used incorrectly.  6. If a piece of code is capable of deadlocking, you cannot eliminate the possibility of deadlocking by inserting invocations of Thread.yield(). (A) 16 (B) 25 (C) 34 (D) 12

221 Which statement is true? (A) This code can throw an InterruptedException. (B) This code can throw an IllegalMonitorStateException. (C) This code can throw a TimeoutException after ten minutes. (D) Reversing the order of obj.wait() and obj.notify() might cause this method to complete normally. (E) A call to notify() or notifyAll() from another thread might cause this method to complete normally. (AB) This code does NOT compile unless "obj.wait()" is replaced with "((Thread) obj).wait()".

222 What is the output if the main() method is run? (A) 4 (B) 5 (C) 8 (D) 9 (E) Compilation fails. (AB) An exception is thrown at runtime. (AC) It is impossible to determine for certain.

223 Which statement is true? (A) The output could be 5-1 6-1 6-2 5-2 (B) The output could be 6-1 6-2 5-1 5-2 (C) The output could be 6-1 5-2 6-2 5-1 (D) The output could be 6-1 6-2 5-1 7-1

224 What is the result? (A) Compilation fails. (B) An exception is thrown at runtime. (C) The code executes normally and prints "foo"; (D) The code executes normally, but nothing is printed.

複選題226 Which two statements are true? (Choose two.) (A) It is possible to synchronize static methods. (B) When a thread has yielded as a result of yield(), it releases its locks. (C) When a thread is sleeping as a result of sleep(), it releases its locks. (D) The Object.wait() method can be invoked only from a synchronized context. (E) The Thread.sleep() method can be invoked only from a synchronized context. (AB) When the thread scheduler receives a notify() request, and notifies a thread, that thread immediately releases its lock.