This is a stupid idea...

DoThis.java

@Post("/account/{accountId}/changeEmail")
public class ChangeEmailRequest {

	private int accountId;
	private String newEmailAddress;

}

// Then the Handler
public class AccountService {

	public void changeEmail(final int accountId, final String email) {
		// ...
	}

	@Subscribe
	public void handleChangeEmailRequest(final ChangeEmailRequest request) {
		this.changeEmail(request.accountId, request.newEmailAddress);
	} 

}

InsteadOf.java

// Instead of
@Path("/account")
public class Account {

	private AccountService accountService;

	@POST("/{accountId}/changeEmail")
	public void changeEmail(int accountId, String newEmailAddress) {
		accountService.changeEmail(accountId, newEmailAddress);
	}

}

public class AccountService {

	public void changeEmail(final int accountId, final String email) {
		// ...
	}
	
}