I have this code and I got this exception from Crashlytics ` kotlinlang #android

10/12/2018, 8:48 AM

I have this code and I got this exception from Crashlytics

Fatal Exception: java.lang.IllegalStateException: readValue(content, jacksonTypeRef<T>()) must not be null

I couldn’t understand what is being null here. Any idea?

10/12/2018, 8:51 AM

This kind of message is ambiguous, but it actually says that a method

readValue(content, jacksonTypeRef<T>())

(probably called by your call to

mapper.readValue(string)

returns null while not allowed to. Or at least that's what I think is happening.

10/12/2018, 8:52 AM

himm let me check the jackson implementation.

so the field is PasswordToken? so it is clearly nullable. the type reference obtained through reified type reference.

inline fun <reified T: Any> ObjectMapper.readValue(content: String): T = readValue(content, jacksonTypeRef<T>())

It should be return null. Anything I am missing here?

10/12/2018, 10:08 AM

T: Any

is not nullable,

T?

T: Any?

is nullable.

For me something defined as

fun <T: Any> foo(): T

cannot return null

10/12/2018, 10:22 AM

ok makes sense.

now I need to figure out how jackson can return null

I have run some tests the only way

mapper.readValue(string)

could return null is when string is null which doesn’t seem to be possible for me.

any ideas on this?

10/12/2018, 12:45 PM

Did you read the actual implementation of the method?

10/12/2018, 12:57 PM

So I figured this finally. “null” string was returned from the SharedPreferences and jackson is returning null in this case.

Gael thank you for your help

10/15/2018, 12:59 PM