```try { myObject.theField } catch(t: Throwabl...

# announcements

[ribesg]

try {
    myObject.theField
} catch(t: Throwable) {
    log.error("theField is null")
}

[horse_badorties]

can you provide the declaration of your data class please?

[horse_badorties]

data class Foo(val name: String)
val myFoo = Foo(null)

does not compile, there is no way of getting a Foo with a null name - the compiler prevents that.

[ribesg]

There are multiple obvious ways to have null values in non null fields

[horse_badorties]

show me one 🙂

[ribesg]

I guess the most obvious one is reflection

[ribesg]

In my specific case it's Moshi

[ribesg]

Retrofit with a MoshiConverter

[horse_badorties]

ok, so we are talking about Interop issues

[ribesg]

Most things running on the JVM do not care about nullability

[horse_badorties]

I wasn't aware you were talking about "kotlin-only"

[ribesg]

You can't do much with Kotlin only 😛

[horse_badorties]

ok, I just did a quick test with a simple static Java method that returns a null String reference.

myObject.theField = JavaTester.returnNull()

throws an IllegalStateException

[horse_badorties]

oops, one moment... 🙂

[horse_badorties]

reflection might work though

[ribesg]

You need either reflection or the Java part stating it doesn't return null using annotations while still returning null

[ribesg]

A simple Java method returning a String is considered to return a String? to a Kotlin caller

[horse_badorties]

exactly

[ribesg]

Now if you put @NotNull on your Java method and still return null, Kotlin is lost

[horse_badorties]

which @NotNull exactly? There are many.

[ribesg]

Any of those understood by the Kotlin compiler I guess

[horse_badorties]

I tried org.jetbrains.annotations.NotNull

[ribesg]

Which should be the same as the ones understood by IDEA by default

[horse_badorties]

still IllegalStateException

[ribesg]

The Java part needs to be compiled separately

[horse_badorties]

org.jetbrains.annotations.NotNull is the IDEA default, yeah

[ribesg]

It needs to be a compiled library

[horse_badorties]

ok, I see

[ribesg]

If it's your own file that you compile at the same time, then it knows

[ribesg]

Another problem is that you really never know how all the alibraries you use work, they may use reflection and you don't know it

[ribesg]

My problem on the Kotlin side is that Kotlin never checks for that null. This object held a null value for days in the RAM, then at some point somebody did an action which passed this value to a method, which doesn't take nulls, and boom. It should have failed earlier. It was very hard to trace

[horse_badorties]

I see. You might want to ask again in the channel and provide a little more background.