How can I control exceptions on Spring Boot startup?

Question

My Spring Boot application tries to load some certificate files on startup. I want to be able to show a sensible message when that file cannot be loaded instead of a huge st

Answer 1

You can catch the BeanCreationException and unwrap it to get the original cause. You can use the following code fragment

public static void main(String[] args) {
    try {
        SpringApplication.run(FileLoadTestApplication.class, args);
    } catch (BeanCreationException ex) {
        Throwable realCause = unwrap(ex);
        // Perform action based on real cause
    }
}

public static Throwable unwrap(Throwable ex) {
    if (ex != null && BeanCreationException.class.isAssignableFrom(ex.getClass())) {
        return unwrap(ex.getCause());
    } else {
        return ex;
    }
}

When the @PostConstruct annotated method throws an exception, Spring wraps it inside the BeanCreationException and throws back.