Is Java EE solutions appropriate for Core banking  projects ?
Personnaly i say "Of course" , and it's not just new technology which is used for core banking projects (Such as TEMENOS T24), also .Net is other alternative which is used for this purpose. But i think Java EE is the best one, because there are lots of operational frameworks  for applying your ideas, patterns and conceptual architecture (most of them are open source under GPL license [Gartner: By 2012, 80 percent of all commercial software will include elements of open-source technology]) which can help  you to reduce the operational risk, costs & improve time to market, maintainability and if you have made the project based on pure Java, you are able to run it from PC to Mainframe.
The main concerns of a core banking project or it is better to say an OLTP system are DBMS ,Transaction Management, Concurrent Processing (Queues & Thread Pools) and Grids, J2EE has good solutions for these issues.

Which Java EE frameworks and technologies  are playing significant roles in this area  ?
It depends on the conceptual and logical architecture! but following concepts maybe help you to make your decision among frameworks:
SOA/SCA
Object Orientation (ORM)
Aspect Orientation
WFMS/BPM/BPEL
Rules
ESB (XML/SOAP/REST/JSON/FIX)
Data & Computational Grids/Cloud