General Discussions

**NullPointer** · 02-07-2008, 06:35 PM

So I started working on a project today and I needed to code up a directed graph in java. Everything is going great for like the first hour, I had all of the underlying structure done (the linked list based adjacency list) and I start building the methods for inserting data and sunddenly eclipse gives me a little wavy red line under one of my assignments. I look at the error message and it says:

Quote:

Type Mismatch: cannot convert from DirectedGraph<V,E>.Vertex<V> to DirectedGraph<V,E>.Vertex<V>

So far I've had no luck at figuring out the underlying error in my design and that message is of very little help. Java is pretty much telling me that it wants something of type vertex... but it can't be of type vertex.

What are some of the completely pointless and unhelpful error messages you guys have seen.. I'm sure those of you who have C++ experience have some.

**Learning Newbie** · 02-07-2008, 07:54 PM

What's the operating system that gives all it's error messages in haiku form? Umbunto or FreeBSD or something?

I didn't know Java could do template based types? Is Vertex<V> a member class of DirectedGraph<V,E> or is it publically accessible by itself?

**NullPointer** · 02-07-2008, 09:37 PM

Java supports generics, which serves the same purpose as template classes in C++ but works a little differently. Vertex<V> is a nested subclass of DirectedGraph. I think I'm going to try externalizing all of my nested classes to see if that solves or at least simplifies my problem.

As far as the haikus go... I'm not sure which OS it is but that's much better than some of the cryptic error messages I've seen.

**ADAM Web Design** · 02-07-2008, 09:46 PM

ASP actually has an "Unspecified Error" message. If I recall correctly, it has something to do with malformed SQL queries. But I haven't seen the error in years.

**ForrestCroce** · 02-07-2008, 09:47 PM

"Permission denied" is a good one, although asp typically only throws that over ntfs permissions. It could mean just about anything, and doesn't sound very helpful.

There's the always popular "object reference not set to an instance of an object." Come to think of it, there's a guy online named after that error...

**fastreplies** · 02-10-2008, 01:14 PM

I hate when error message says: Contact Administrator
Hmmm... contact myself

fastreplies