What is an AssertionError? In which case should I throw it from my own code?

Question

In Item 2 of the \"Effective Java, 2nd edition\" book, there is this snippet of code, in which the author wants to forbid the empty initialization of an object.

Answer 1

AssertionError is an Unchecked Exception which rises explicitly by programmer or by API Developer to indicate that assert statement fails.

assert(x>10);

Output:

AssertionError

If x is not greater than 10 then you will get runtime exception saying AssertionError.