OCPJP Simulation Test 60

60

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Question List

Question: Given Collection<? super Exception> queue = new ArrayList<Exception>(), what are the following code compiles?

Choice:
A. queue.add(new Object());
B. queue.add(new OutOfMemoryError());
C. queue.add(new IOException());
D. queue.add(new NumberFormatException());
E. queue.add(new FileNotFoundException());
F. queue.add(new Error());
G. queue.add(new IndexOutOfBoundsException());
H. queue.add(new StackOverflowError());



Next Question

Answer: C, E

Explain: regardless of the right side assignment, only the left side type declaration counts: Queue<? super IOException> queue. You can only add the subclass of IOException to the queue. Of course you need to be familiar with common java Exceptions, which is a topic of OCAJP.

Study:  Create and use a generic class