@Component public class PaymentSnowFlakeIdGenerator { @Resource private UidSoaGenerateService uidSoaGenerateService; @Resource private PaymentSnowFlakeIdGenerator paymentSnowFlakeIdGenerator; public static PaymentSnowFlakeIdGenerator INSTANCE = paymentSnowFlakeIdGenerator; public long generateId64(){ return uidSoaGenerateService.getId(); } }

在代码中存在以下问题：

1. `private PaymentSnowFlakeIdGenerator paymentSnowFlakeIdGenerator;` 这行代码会导致空指针异常，因为 `paymentSnowFlakeIdGenerator` 还未被初始化就被用于初始化 `INSTANCE`，需要将其改为 `private static PaymentSnowFlakeIdGenerator paymentSnowFlakeIdGenerator;`。

2. `public static PaymentSnowFlakeIdGenerator INSTANCE = paymentSnowFlakeIdGenerator;` 这行代码也会导致空指针异常，因为 `paymentSnowFlakeIdGenerator` 还未被初始化就被用于初始化 `INSTANCE`，需要将其改为 `public static PaymentSnowFlakeIdGenerator INSTANCE = new PaymentSnowFlakeIdGenerator();`。

修改后的代码如下：

@Component
public class PaymentSnowFlakeIdGenerator {
    @Resource
    private UidSoaGenerateService uidSoaGenerateService;

    private static PaymentSnowFlakeIdGenerator paymentSnowFlakeIdGenerator;

    public static PaymentSnowFlakeIdGenerator INSTANCE = new PaymentSnowFlakeIdGenerator();

    private PaymentSnowFlakeIdGenerator() {
        paymentSnowFlakeIdGenerator = this;
    }

    public long generateId64() {
        return uidSoaGenerateService.getId();
    }
}

这里我还添加了一个私有构造函数，使得 `paymentSnowFlakeIdGenerator` 在实例化时能够正确地初始化。