Assertions

[Sarma Lolla]

5.28 Given the following method, which of these statements will throw an exception,
assuming assertions are enabled?
static int inv(int value) {
assert value > -50 : value < 100;
return 100/value;
}
Select the two correct answers.
(a) inv(-50);
(b) inv(0);
(c) inv(50);
(d) inv(100);
(e) inv(150);
While AssertionError is not an exception but an error. The answer to the above questions should be only B where we get Arithmetic Exception.
For answer A we get AssertionError.
Answers given are:
5.28 (a) and (b)
Statement (a) will cause the assert statement to throw an AssertionError, since (-
50 > -50) evaluates to false. Statement (b) will cause the expression 100/value to
throw an ArithmeticException, since an integer division by zero is attempted.
[ March 15, 2003: Message edited by: Sarma Lolla ]

[Marlene Miller]

I was curious to see how the JLS classified subclasses of Error. Are they exceptions?

Those unchecked exception classes which are the error classes (Error and its subclasses) are exempted from compile-time checking because they can occur at many points in the program and recovery from them is difficult or impossible. JLS 11.2.1

The possible exceptions in a program are organized in a hierarchy of classes, rooted at class Throwable (�11.5), a direct subclass of Object. The classes Exception and Error are direct subclasses of Throwable. The class RuntimeException is a direct subclass of Exception. JLS 11.5

The class Error and its subclasses are exceptions from which ordinary programs are not ordinarily expected to recover. JLS 11.5

[Sarma Lolla]

Marlene,
So JLS itself is using the word exception to include both errors, run time exceptions and checked exceptions.
The problem is if you know how many answers you need to select to this question the question wouldn't arise.

[Marlene Miller]

Yes, the JLS categorizes both classes Error and Exception as exceptions. (This surprised me, too.) But the assert spec assert-spec.html and the assert guide assert.html never refer to AssertionError as an exception.

[Sarma Lolla]

Yes, the JLS categorizes both classes Error and Exception as exceptions. (This surprised me, too.) But the assert spec assert-spec.html and the assert guide assert.html never refer to AssertionError as an exception.

Hmmmmmm after thought for SUN?