Having Apache on the EC (Executive Committee) strengthened Java by giving an official voice to the (large) open source Java community. This was useful for Java because Apache often agitated to make sure specifications were licensed under terms that are compatible with open source implementations. Open Source implementations have kept Java competitive with .NET in terms of price, and many specifications have grown out of open source Java projects.
The Eclipse organisation remains on the EC, so Oracle can point to them as a voice for open source. However, Eclipse is different to Apache in that it is primarily a pay-to-play organisation, whilst Apache is a meritocracy.
In terms of specifications themselves (JSRs), Apache will no longer automatically have a representative. Individual experts can still be invited, but Apache's withdrawal (as well as that of people like Doug Lea & Bob Lee) makes it less likely experts will want to serve on a JSR committee.