Introduction to Programming Languages/Checked exceptions

Checked vs Unchecked Exceptions This is one of the most important Java concepts. Java divides exceptions into: checked; unchecked. Unchecked Exceptions These are: RuntimeException; Error; subclasses of them. The compiler does NOT force handling. Example:ArithmeticException Checked Exceptions All other exceptions. The compiler forces you to: handle them; OR declare them. Example:void z() { throw new OutOfGas(); }This does NOT compile.Because OutOfGas is checked. Throws We must declare:void z() throws OutOfGas { throw new OutOfGas(); } Intuition Behind throws It means: “This method may throw this exception”. Propagation If one method calls another that throws a checked exception: it must also handle it; OR propagate it. Advantage of Checked Exceptions They work as: verified documentation. The compiler guarantees: that nobody silently ignores the error. Disadvantages Many programmers consider them: verbose; tiring; excessively bureaucratic. That is why modern languages often avoid this model.