The following quote summarises their motivations for choosing Groovy and Grails:
"First, we needed a scripting language that runs in the JVM, so that ruled out some languages right there. Anything that runs outside the JVM will require some duplication of processes, and interprocess communication is more complicated. Second, we felt that Hibernate and Spring were well proven and we wanted to take advantage of them. Finally, the Groovy syntax and lifecycle management is very Java-like. This matters because the availability of skilled programmers is crucial in the enterprise space, and there are loads of Java developers out there."
It is a great to see a company as large of SAP who "gets it". Good job.