interface  InternalCombustionEngine  { /* ... */ }

abstract class FourStrokeEngine implements InternalCombustionEngine  { /* ... */ }

class GeneralMotorsLS3 extends FourStrokeEngine { /* ... */ }

class ChevroletCorvette implements InternalCombustionEngine {
    FourStrokeEngine engine;

    /*
     * Receive abstract class so that changes in it can transparently
     * update all classes that extend the abstract class.
     */
    void setEngine(FourStrokeEngine e) { engine = e; }

    // Return interface rather than concrete class to allow widest possible use
    InternalCombustionEngine getEngine() { return engine; }

    public static int main(String[] args) {
        var corvette = new ChevroletCorvette();
        corvette.setEngine(new GeneralMotorsLS3());
        return 0;
    }
}