public MapStoreConfig setImplementation(@Nonnull Object implementation) {
        this.implementation = checkNotNull(implementation, "Map store cannot be null!");
        this.className = null;
        return this;
    }
@Test
    public void setImplementation() {
        Object mapStoreImpl = new Object();
        MapStoreConfig cfg = new MapStoreConfig().setImplementation(mapStoreImpl);
        assertEquals(mapStoreImpl, cfg.getImplementation());
        assertEquals(new MapStoreConfig().setImplementation(mapStoreImpl), cfg);
    }