eclipselink migration : could not find openjpa specific code

Question

I am migrating from openjpa (2.2.2) to eclipselink(2.5.2) in my legacy project. During migration, I could see following code snippet which is specific to openjpa:

openjpaEntityManager kem = openjpaPersistence.cast(em);
kem.getFetchPlan().addField(Test.class, "stringvalue");
kem.getFetchPlan().addField(Test.class, "other string value");
if (!(em instanceof openjpaEntityManager)) {
kem.close();
}

Please help to find corresponding eclipselink related code to this code snippet.