package com.baeldung.akkahttp; import java.io.Serializable; public interface UserMessages { class ActionPerformed implements Serializable { private static final long serialVersionUID = 1L; private final String description; public ActionPerformed(String description) { this.description = description; } public String getDescription() { return description; } } class CreateUserMessage implements Serializable { private static final long serialVersionUID = 1L; private final User user; public CreateUserMessage(User user) { this.user = user; } public User getUser() { return user; } } class GetUserMessage implements Serializable { private static final long serialVersionUID = 1L; private final Long userId; public GetUserMessage(Long userId) { this.userId = userId; } public Long getUserId() { return userId; } } }