how to write a custom error message in java code example

Example 1: java define custom exception

public class CustomException extends Exception { 
    public CustomException(String errorMessage) {
        super(errorMessage);
    }
}

Example 2: java exception override message

// Most exception classes provide a constructor requesting a String.
// Check the API of your superclass.

public class PersonalException extends RuntimeException{
  
	public PersonalException() {
		super("This is a message for you! Something went wrong...");
	}
}