A record that validates itself in Java
Java interview exercise on Records, classes & interfaces, 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 record Range(int low, int high) whose compact constructor throws IllegalArgumentException (message mentioning "low") when low > high, with methods contains(n) (inclusive at both ends) and length() (high - low).
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.