To answer this question, the user needs to understand the basic functionality of the Set collection in Java.
Option A is incorrect. When attempting to add an element to a Set that already exists in the Set, an exception is not thrown. Instead, the Set simply ignores the duplicate element and does not add it to the collection.
Option B is correct. The add method of a Set returns a boolean value of false if the element being added already exists in the Set. This is because Sets do not allow duplicate elements.
Option C is incorrect. Sets are designed to contain only unique elements. If an element already exists in the Set, it will not be added again. Therefore, a Set cannot contain elements that return duplicate values from a call to the equals method.
Option D is incorrect. Duplicate values will not cause an error at compile time. Instead, the Set will simply ignore the duplicate value when the code is executed.
Therefore, the correct answer is:
The Answer is: B. The add method returns false if you attempt to add an element with a duplicate value.