Spark: Spark swallows exceptions

[wowselim]

Whenever I write code that causes e.g. a NullPointerException, like calling methods on an Object that is null, eclipse does not print any exceptions at all. See following code:

credentials = new HashMap<>();
if(credentials.get("user").equals("password")) { ... }

Now I didn't realize get() would return null if the key wasn't in the HashMap. However running this code gave me a 500 serverside error, while eclipse did not print a single exception. I had to find and fix the error myself like so:

String storedPassword = credentials.get("user");
if(storedPassword != null && password.equals(storedPassword)) { ... }

Please note: I have slf4j in my pom.xml and buildpath:

<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-simple</artifactId>
    <version>1.7.21</version>
</dependency>

[lewtds]

You can register a catch-all Spark exception handler to log uncaught exceptions:

Spark.exception(Exception.class, (exception, request, response) -> {
    exception.printStackTrace();
});

IMHO, this should be the default behavior tho.

[wowselim]

@lewtds thank you, that would print the Exception expected in the faulty code above. However if there are no Exceptions printed at all it's a maddening process to go and find the wrong pieces yourself especially if your codebase is large I believe. Thus I also think this should be the default.

[CarlosMChica]

I did that, but when doing so the return status code in the response is 404 instead of 500 (expected). Does this happen to you as well?

[MouettE-SC]

This is the same as #486

[kospol]

lewtds's solution works, but I still don't get the expected behavior on 2.5.2.