1Z0-819 Exception Handling & Concurrency 2

Question 1

What happens when both the try block and the finally block throw exceptions?

Accepted Answer

The finally block's exception propagates and the try block's exception is lost

Answer

The exception thrown in the finally block replaces the one from the try block, causing the original exception to be silently lost.

Question 2

Which interface must a class implement to be used as the target of a Thread?

Accepted Answer

Runnable

Answer

The Runnable functional interface (with its run() method) is the standard contract for thread task targets.

Question 3

What does ReentrantLock.tryLock() return if the lock is already held by another thread?

Accepted Answer

It returns false immediately

Answer

tryLock() is a non-blocking acquire attempt that returns false immediately if the lock cannot be obtained.

Question 4

Which exception is thrown when a thread is interrupted while waiting in Object.wait()?

Accepted Answer

InterruptedException

Answer

Object.wait() declares throws InterruptedException, which is thrown when the waiting thread's interrupt status is set.

Question 5

What is the output of: try { throw new RuntimeException(); } catch (Exception e) { System.out.print("A"); } finally { System.out.print("B"); }

Accepted Answer

AB

Answer

The catch block prints 'A', then the finally block always executes and prints 'B', giving 'AB'.

(1Z0-819) Oracle Java SE 11 Developer Practice Test