A custom checked exception in Java
Java interview exercise on Exceptions & validation, difficulty 1 of 3. Solve it in the editor beside a worked example, or cold in Interview mode with the example hidden; the tests run the moment you do.
Write class InsufficientFundsException extends Exception with a constructor taking the shortfall (a long) and a getter shortfall(), and its message reading "Short by <n>". Then withdraw(balance, amount) that returns the new balance, or throws that exception when amount exceeds balance. Being checked, the method must declare it.
Each exercise pairs a worked example with a twin problem to solve in a real editor; the tests run the moment you do. Interview mode hides the example: solve it from memory, without the hint or the solution, and it counts as solved cold. Progress is saved in your browser, and in your account if you sign in.