Practice: Using throw to Manually Raise Exception

Write the single statement that manually raises an ArithmeticException with the message "Invalid input", and explain what each part of it does.

In the lesson's example, age is 15 and the program ends by printing Exception in thread "main" java.lang.ArithmeticException: You are underaged!. Which line causes this, and why does the program stop instead of carrying on?

Which keyword manually raises an exception?

Which statement correctly raises an exception?

Build a validator for a registration form. Write validateUsername(String name) that throws an IllegalArgumentException when the name is empty, shorter than 3 characters, or contains a space, each with its own message. In main, test "anjali_07", "", "ab", "ravi kumar" and "dev2024", printing a success message or the error message for each one. Two String methods help: name.isEmpty() returns true when the string has no characters at all, and name.contains(" ") returns true when the string has a space anywhere in it.

A temperature sensor sometimes sends impossible readings. Create a custom SensorException and a method readTemperature(int raw) that throws it when a reading is outside -50 to 150. Process the readings 23, 25, 999, 24, -80 and 26: print each valid reading, skip each invalid one with a message, and finally print how many readings were valid and invalid and the average of the valid ones.