I created a simple rest service using java, and springboot. here is my service layer code
@Service
class MyService {
private final TestService service;
@Autowired
public MyService(final TestService service) {
this.service = service;
}
// here is the issue
private final Predicate<User> userPredicate = (user) -> this.service.isValidUser(user);
}
In the above line, the ide complaining about the variable service might not be initialized, and I can not use it in the predicate implementation. I tried removing final to the service, that works, but I do not want to remove final to the TestService declaration.
Anyone have any solution ?
Execution order is: First all initializing expressions are resolved in lexical order (top to bottom through the file), then the constructor runs.
In other words, that userPredicate = line runs before your this.service = service; line. It's doomed to failure, and the compiler knows it, so it will refuse to compile this code.
The fix is trivial - move that userPredicate initialization into the constructor:
private final TestService service;
private final Predicate<User> userPredicate;
@AutoWired
public MyService(TestService service) {
this.service = service;
this.userPredicate = user -> service.isValidUser(user);
}
For what its worth, if you don't need the service for anything except making that userPredicate, might as well get rid of the service field entirely.