Why? Well over the years we've learnt a lot of lessons of how to build Scalable Java applications. Even then, some people can't seem to get it right (No names , but you know who you are). How would SAP people (who I have a lot of respect for as you don't get to the position SAP is within the industry without getting at least something right) react to this strange new Java world. Would they shed all past baggage and dive in with the enthusiasm of College Graduates? Or would they take a 'not invented here' attitude and hack together something in Java along the lines of what they were used to.
I suspected the latter , and fully expected to end up cleaning up some mess of a CRM or ERM system. However, I am pleasently surprised with SAP's Java Website. On a pure Java level, it approaches the efforts from Oracle , IBM and BEA. If SAP are making this amount of effort to promote Java best practice, then there may be hope after all.
Final question: If this goes the way SAP is planning, at what point does it's installed base get counted as part of the Market share of J2EE servers. What percentage of the market would it have? A healthy and very profitable 10%? Certainly the strategy (and the Market share) is very close to Oracle , which also bundles it's (10g) App server with it's main product (a Database rather than a CRM or ERP Solution).