IllegalArgumentException or NullPointerException for a null parameter? [closed]

Answer 1

Ideally runtime exceptions should not be thrown. A checked exception(business exception) should be created for your scenario. Because if either of these exception is thrown and logged, it misguides the developer while going through the logs. Instead business exceptions do not create that panic and usually ignored while troubleshooting logs.

Answer 2

If it's a "setter", or somewhere I'm getting a member to use later, I tend to use IllegalArgumentException.

If it's something I'm going to use (dereference) right now in the method, I throw a NullPointerException proactively. I like this better than letting the runtime do it, because I can provide a helpful message (seems like the runtime could do this too, but that's a rant for another day).

If I'm overriding a method, I use whatever the overridden method uses.