Provider method workaround for classpath

[charphi]

In Java 9+, a provider method is a public static no-arg method called provider where the return type is the service type.

Since this feature is not available on Java 8, a possible workaround would be to generate a delegate wrapper around this method.

[charphi]

Workaround could be extended to:

• public static method that returns service
• public enum that implements service

Examples:

public interface HelloService {}

public class SomeClass {
  @ServiceProvider
  public static HelloService create() { ... }
}

@ServiceProvider
public enum SomeEnum implements HelloService { ... }