OCPJP Simulation Test 63

63

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Question List

Question: Given Set<? super Error> set = new HashSet<Throwable>(), what are the following code compiles?

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



Next Question

Answer: F, H

Explain: regardless of the right side assignment, only the left side type declaration counts: Set<? super Error> set. You can only add the subclass of Error 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