Question

You're migrating an Android service layer from Java to Kotlin and let an AI agent auto-convert files. The converted Kotlin compiles and you ship it to the beta channel, where you start seeing a spike in NullPointerExceptions that the old Java code 'never had.' Below is the kind of signature the agent produced — explain the trap.

1// Java method returned a value annotated @Nullable in some callers' minds2// but had no annotation. Agent converted it as:3fun loadProfile(id: String): UserProfile {  // non-null return type4    return repository.find(id)  // can return null at runtime5}