1Z0-819 Exception Handling & Concurrency 3

Question 1

Which method of ExecutorService blocks until all submitted tasks complete or a timeout occurs?

Accepted Answer

awaitTermination(long, TimeUnit)

Answer

awaitTermination() blocks the calling thread until the executor terminates or the specified timeout elapses, returning a boolean result.

Question 2

What kind of exception is java.io.IOException?

Accepted Answer

Checked exception

Answer

IOException extends Exception (not RuntimeException), making it a checked exception that must be declared or handled.

Question 3

What does Callable differ from Runnable in terms of return value and exceptions?

Accepted Answer

Callable returns a typed value and can throw checked exceptions

Answer

Callable<V> defines call() which returns V and declares throws Exception, unlike Runnable's run() which returns void and cannot throw checked exceptions.

Question 4

Which exception is thrown by BlockingQueue.take() when the current thread is interrupted?

Accepted Answer

InterruptedException

Answer

BlockingQueue.take() blocks until an element is available and throws InterruptedException if the thread is interrupted while waiting.

Question 5

In a multi-catch block 'catch (IOException | SQLException e)', what is the type of 'e'?

Accepted Answer

A union type that can only be rethrown

Answer

In a multi-catch, the variable is implicitly final and typed as the union; it can only be rethrown as-is, not reassigned.

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

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

1Z0-819 Exception Handling & Concurrency 3