When running EclipseLink JPA outside of the container you do need to use
the -javaagent:eclipselink.jar on the command line when you launch the
application. This enables the byte-code weaving necessary for 1:1 and M:1
lazy loading.
Our JPA implementation only uses the Server/Client session under the
covers. For 2-tier applications you can simply configure the internal
connection pool to use 1 read and 1 write connection.