src/main/java/com/alipay/remoting/rpc/RpcResponseResolver.java
private static Throwable toThrowable(ResponseCommand responseCommand) throws CodecException {
        RpcResponseCommand resp = (RpcResponseCommand) responseCommand;
        resp.deserialize();
        Object ex = resp.getResponseObject();
        if (ex != null && ex instanceof Throwable) {
            return (Throwable) ex;
        }
        return null;
    }
private static Throwable toThrowable(ResponseCommand responseCommand) throws CodecException {
        RpcResponseCommand resp = (RpcResponseCommand) responseCommand;
        resp.deserialize();
        Object ex = resp.getResponseObject();
        if (ex != null && ex instanceof Throwable) {
            return (Throwable) ex;
        }
        return null;
    }
Convert remoting response command to throwable if it is a throwable, otherwise return null.