Repository implementation with generics

RepositoryWithGenerics.groovy

interface Repository<T> {
   T save(T t)
}

interface IntegerRepository {
   Integer findByIntegers(String name)
}

abstract class InMemoryRepository<A> implements Repository<A> { 
    A save(A a) {
        println a.getClass()
    }
}

class IntegerInMemoryRepository extends InMemoryRepository<Integer> implements IntegerRepository {
    Integer findByIntegers(String name) {
        return 10
    }
}

class StringInMemoryRepository extends InMemoryRepository<String>{}

new EventInMemoryRepository().save(3)
new StringInMemoryRepository().save(3)