Static methods live inside one virtual machine and it is you who must take resposibility to "scale" solution and take other decisions on mny other issues.
On other hand, J2EE containers does much the dirty work for you. You just need to give some details in deplayment descriptors.
Container will decide how many instances of the loader/saved it needs to serve all incoming requests with optimal latency. Also J2EE edition of the loader/saver might be scaleable between many machines if J2ee container supports scaling.
I'd prefer staless bean which operates with local enity beans. It should be slower than usual static method but it will bring all the advances from message above.