Migration of a VB6 application

Question

Migation of a VB6 application to .NET platform is almost like a rewrite, no matter it is VB.NET or C#. Do you think it will require more effort to do it in Java platform, when compared to .NET platform, since it is a rewrite anyway? Please share your thoughts!

Answer 1

No offence, but you are wrong. Porting to .Net is usually far easier than a rewrite.

Here's the official advice from Microsoft UK:

Performing a complete rewrite to .NET is far more costly and difficult to do well [than converting] ... we would only recommend this approach for a small number of situations.

From a blog post by a Microsoft guy who consulted on rewrites:

Many companies I worked with in the early days of .NET looked first at rewriting driven in part by a strong desire to improve the underlying architecture and code structures at the same time as they moved to .NET. Unfortunately many of those projects ran into difficulty and several were never completed. The problem they were trying to solve was too large

I recommend the following two steps in this order.

1. Write down the reasons for migration or rewriting. What benefits will it bring? The benefits might be just to keep the development team happy - that might even be a good enough reason, I don't know. Make sure you know, and your managers/users agree.
2. Check out the Microsoft UK advice with a screencast explaining the 5 basic options for .Net migration. Decide which is best. It may be rewriting, but go into it with your eyes open.

In answer to your actual question: would a complete rewrite be easier in .Net or Java? That mainly depends on which one your team knows best. It also depends a little on whether the application interacts with COM, just like SLaks says.