I'm currently a sophomore in APCS after taking a year of the base Java class. Both focus on the language for the most part. In APCS, ~60% of the material is Java OOP, as in specifics behavior when overriding methods, static vs instance, interfaces etc. 20-25% is control structures, syntax etc, and in first semester we've covered basic sorts, built in arrays and ArrayLists. I believe in second semester we talk about elementary data structures like linked lists and _maybe_ binary trees after the AP exam (the class is structured around CollegeBoard's AP exam).

Since there is already a Java class on campus, I think the AP class should focus more on language independent CS concepts. At least half of our final and tests are problems about determining what is printed by an obfuscated Java program to test knowledge of how edge cases are handled.