java.io.NotSerializableException

Question

我无法找到两个（不同类）对象中的一个无法序列化/反序列化的原因。

LoginRequestProtocol对象被发送到我的服务器，反序列化，我的服务器开始处理请求。请求被提交后不久，我正在尝试发送响应，这就是失败的地方。我错过了什么？

第一个发送没有任何问题的对象：

public class LoginRequestProtocol implements Serializable{

private static final long serialVersionUID = 1L;

public final LoginRequest REQUEST;

private String[] body = null;

public LoginRequestProtocol(LoginRequest type) {
    REQUEST = type;
}

public boolean setRequestBody(String... args) {
    Log.debug("Setting LoginProtocolRequest body...", 0);
    if (args.length > 0) {
        body = args;
        Log.debug(" body size: " + body.length + ".", 1);
        return true;
    } else {
        Log.debug(" failure.", 0);
        Log.warning("Data passed for the body was empty.");
        return false;
    }
}
public String[] getRequestBody() {
    Log.debug("Extracting LoginProtocolRequest body...", 0);
    if (body == null || body.length < 1) {
        Log.debug(" failure.", 1);
        Log.warning("Data passed for the body was empty.");
        return null;
    } else {
        Log.debug(" body size: " + body.length + ".", 1);
        return body;
    }
}

}

第二个对象 - LoginResponseProtocol无法执行此操作。

package common.network;

import java.io.Serializable;

public class LoginResponseProtocol implements Serializable{

private static final long serialVersionUID = 1L;

public final LoginResponse RESPONSE;

public LoginResponseProtocol(LoginResponse response) {
    RESPONSE = response;
  }
}

注意：LoginRequest和LoginResponse是枚举。

服务器说：

java.io.NotSerializableException: common.network.LoginResponseProtocol
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.writeObject(Unknown Source)

客户说：

java.io.WriteAbortedException: writing aborted; java.io.NotSerializableException: common.network.LoginResponseProtocol
    at java.io.ObjectInputStream.readObject0(Unknown Source)
    at java.io.ObjectInputStream.readObject(Unknown Source)

更新：LoginResponse：

package common.network;

public enum LoginResponse {

OK,
ERROR_CONNECTION,
ERROR_SQL,
FAIL

}