Java Guice: If you inject the same dependency multiple times, is the same instance of that dependency injected?

Question

I have a java jersey 2.x project, using Guice as my dependency injection framework. I have this service

public class AccountService {

private final AccountRepository accountRepository;

@Inject
public AccountService(InMemoryAccountRepositoryImpl inMemoryAccountRepositoryImpl) {
    this.accountRepository = inMemoryAccountRepositoryImpl;
}

Let's say that I create another service class that also injects InMemoryAccountRepositoryImpl , will the same instance be injected? It's important for me to know, because this instance has an internal state that needs to be consistent.

Answer 1

By default, Guice returns a new instance each time it supplies a value. This behaviour is configurable via scopes. Scopes allow you to reuse instances: for the lifetime of an application (@Singleton), a session (@SessionScoped), or a request (@RequestScoped). Guice includes a servlet extension that defines scopes for web apps. Custom scopes can be written for other types of applications.

for more info see the documentation