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.

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

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.

227 What can be a result? (A) Compilation fails. (B) An exception is thrown at runtime. (C) The code executes and prints "StartedComplete". (D) The code executes and prints "StartedComplete0123". (E) The code executes and prints "Started0123Complete".

228 Which three will compile and run without exception? (Choose three.)  1. private synchronized Object o;  2.  3. public synchronized void go(){/* code here */}  4. private synchronized(this) void go(){/* code here */}  5.  6.  (A) 123 (B) 235 (C) 356 (D) 456

複選題229 Which two changes, taken together, would guarantee the output: 1, 2, 3, 4, 5, ? (Choose two.) (A) move the line 12 print statement into the foo() method (B) change line 7 to public synchronized void go(){ (C) change the variable declaration on line 2 to private volatile int x; (D) wrap the code inside the foo() method with a synchronized(this) block (E) wrap the for loop code inside the go() method with a synchronized block synchronized(this){//for loop code here}

230 Given that t1 is a reference to a live thread, which is true? (A) The Thread.sleep() method can take t1 as an argument. (B) The Object.notify() method can take t1 as an argument. (C) The Thread.yield() method can take t1 as an argument. (D) The Thread.setPriority() method can take t1 as an argument. (E) The Object.notify() method arbitrarily chooses which thread to notify.

231 What is the result? (A) Cat (B) Dog (C) Compilation fails. (D) The code runs with no output. (E) An exception is thrown at runtime.