1) On a method call somewhere in a stack with no null checks: here it's not very useful to have an NPE, since it should work (eg. there's no null checks, so why should it fail?).

2) `Objects.requireNonNull(o)` (or an explicit through). This indicates that a pre-condition is that the object should not be null. These tell that the fault is in the preceding call stack, therefore you don't even need to understand what the underlying one is to know where the error is coming from.

Although all types are nullable in Java, I don't expect _everything_ to be null-checked. Nullable types in Rust stand out, therefore should be matched or checked. If I have a panic due to a naked `unwrap()`, either there's a documented pre-condition and the system isn't recoverable (hence the crash), or the error handling is missing and I know what to do.

Hence `unwrap()` is similar to (2), which are useful panics.