Kotlin objects are actually just singletons. Its primary advantage is that you don't have to use SomeSingleton.INSTANCE
to get the instance of the singleton.
In java your singleton looks like this:
public enum SharedRegistry {
INSTANCE;
public void register(String key, Object thing) {}
}
public static void main(String[] args) {
SharedRegistry.INSTANCE.register("a", "apple");
SharedRegistry.INSTANCE.register("b", "boy");
SharedRegistry.INSTANCE.register("c", "cat");
SharedRegistry.INSTANCE.register("d", "dog");
}
In kotlin, the equivalent code is
object SharedRegistry {
fun register(key: String, thing: Object) {}
}
fun main(Array<String> args) {
SharedRegistry.register("a", "apple")
SharedRegistry.register("b", "boy")
SharedRegistry.register("c", "cat")
SharedRegistry.register("d", "dog")
}
It's obvoiusly less verbose to use.