Want to Contribute to us or want to have 15k+ Audience read your Article ? Or Just want to make a strong Backlink?

7 Programming Riddles That Even Elite Coders Can’t Solve

In 1996 Phil Karlton stated:

There are solely two arduous issues in Pc Science: cache invalidation and naming issues.

This quote developed in different ways and my favourite one is:

I’m not as skilled as the blokes above nonetheless I’ve my private checklist of annoying programming points I’m dealing with steadily. That is this checklist – a set of the advanced subjects in programming that haven’t any resolution but backed by my tales (positive, unique issues are included, seems like they’re everlasting):

  1. Cache invalidation
  2. Scrolling
  3. When to upgrade?
  4. Naming things
  5. N+1
  6. Dates

Cache invalidation

In a nutshell, cache invalidation is a tricky problem. It’s been one of the cussed issues in programming for many years, and we’re nonetheless trying to find the one resolution to rule all of them. At any time when this drawback exhibits up, it eats away at our helpful time.

From my very own programming journey, I’ve discovered that the key headache of cache invalidation is not about deciding when it is time to invalidate the cache, balancing efficiency, and knowledge accuracy. No, the actual drawback is Understanding that the issue comes from the cache.

The sequence often unfolds like this:

  • The help staff flags a priority – the shopper adjustments issues, and the system says it is okay, however the outdated data stays there.
  • You attempt to replicate it in your native machine or the dev or staging server – the whole lot’s flawless there.
  • Certain, you are diving in to know extra concerning the scenario, asking questions comparable to:
    • Did the replace actually undergo?
    • Is there a bug inflicting the system to assert success prematurely?
    • If the replace was carried out, was the information refreshed correctly?
  • After a protracted and thorough test, you discover that the whole lot appears high quality, however frustratingly, the issue would not occur fairly often.
  • Later, after spending many hours making an attempt to repair the difficulty, you uncover a hidden if/else assertion that was added by somebody who left the corporate two years in the past.
  • Cease. Pause. Suppose. F*ck it. Abruptly, you understand it’s a novel caching setup for a selected scenario that you just would not anticipate until you knew about it beforehand. However actually, how may you will have guessed?

That is simply one-half of the issue. What if the caching system lurks outdoors your code? My favourite troublemaker right here is Hibernate. For these accustomed to Hibernate, you understand precisely what I am speaking about. For many who aren’t, let’s simply say you are in for an enormous shock.

Even after trying by way of a lot of articles and movies, each few months, I encounter errors due to Hibernate. In the case of caching, Hibernate could be a ruthless monster, able to devour your peace of thoughts until you deal with it with excessive warning.


I’ve expertise in each frontend and backend growth, however with my roots in frontend, I’ve developed a firsthand understanding of the fascinating world of scrolls. Belief me, it is extra twisted than one may anticipate.

Primarily, customization! These delicate parts in your browser are distinctive throughout completely different platforms – be it Mac, Linux, or Home windows, and to not point out browsers comparable to Chrome, Safari, or Firefox. Regardless that their look differs in all places, they resist you while you attempt to customise their look uniformly throughout platforms, which frustrates our design staff.

The story takes one other twist once we usher in our love for MacBooks and our choice for hiding scrolls in our browsers. Unintentionally, we blind ourselves to blatant scrolling points that go off to see the world in manufacturing. Shock, shock, scrolls pop up in probably the most surprising locations!

To sort out this, we created a devoted channel to publish about any scrolling anomalies we come throughout:

default scroll in heading

default scroll in json editor

default scroll in actions

In the meantime, our design preferrred stays the common-or-garden “Small Neat Scroll”

correct slim scroll

As a countermeasure in opposition to unleashing erratic scrolls onto the manufacturing stage, we developed a easy but efficient method: Set scroll visibility to ‘all the time’ in Mac settings. Voila! This proved to be an environment friendly stopgap resolution to trim down such points in manufacturing. Who stated all options should be advanced?

Additionally, credit score to my teammate Alex for utilizing Firefox when the remainder of us had been crusing on the Chrome ship. Due to this, many pesky CSS bugs met their finish.

So, this is a professional tip: use completely different browsers. Certain, you possibly can go for a posh resolution like establishing a browser stack on your CSS points, however it’s not the possible alternative for each staff. Nonetheless, testing your mission in two or three main browsers that your consumer makes use of can drastically provide help to nip points within the bud.

However hey, it is not simply my staff battling these scroll-based outlaws. As we found, the world of coding is a lot more scroll-stricken than we had thought.

When to improve?

To improve, or to not improve – that’s certainly one in every of our largest questions in programming. The query of ‘When to improve’ has been a long-standing problem. Basically, it comes down to 2 most important components:

  1. Builders are all the time eager on maintaining step with the latest variations of libs and frameworks.
  2. Managers are motivated to roll out the most recent product variations to purchasers.

Now, let’s delve proper in and weigh the professionals and cons on this see-saw of upgrading:


  • Efficiency Increase: Upgrades can improve your software program’s efficiency.
  • New Options: Upgrades typically include thrilling new options, upping your tech sport.
  • Bug Fixes: In the event you’ve been scuffling with sure bugs, upgrades is perhaps your savior.


  • Potential Bugs: Each new addition comes with the chance of bugs. Bug fixes may be time-consuming and decrease your confidence within the new code.
  • Breaking Modifications: Upgrades are sometimes tagged together with breaking adjustments. As an example, with Node 16 help being dropped by Angular 17, the difference time significantly will increase.

Making use of upgrades can undoubtedly convey many advantages, however they can be a Pandora’s field of unexpected issues. You may marvel – How a lot work would it not take to transition from Node 16 to Node 18 in a mission? A easy model change, or a time-consuming seek for the right variations of all packages?

Personally, I am on the cautious facet in the case of upgrades. Nonetheless, some teammates are eager on them, and collectively, we have discovered a steadiness to maintain our software program up to date, or at the least near the most recent variations with minimal disruptions.

That is the case now, however earlier than…

Backtracking a couple of years, we had an intriguing encounter with a brand new consumer, eager on deploying our software program (https://uibakery.io/) on-premise. We supplied him with a deployment information, and surprisingly, he got here again with a safety report mentioning lots of of points, with tens of them as important vulnerabilities!

Curiously, all the key issues in our pictures may have been mounted simply with an everyday replace – probably saving us from shedding the consumer! This incident made us understand the facility of staying up to date. Since then, we have made it some extent to carry out safety scans earlier than any rollout.

In conclusion, discovering the correct time to improve is all about putting a steadiness and understanding your mission’s particular wants.

Naming issues

Any idiot can write code that a pc can perceive. Good programmers write code that people can perceive.
—- Martin Fowler

One of many easiest, but essential undertakings in any coding mission, is to appropriately title issues. Seeing is believing, so let’s take a look at two bites of code:

The primary one, as you may agree is a riddle, demanding an intensive learn to decrypt its objective.

public class LN {
    public static void most important(String[] args) {
        B b = new B();
        b.s(1, "Harry Potter");
        b.s(2, "Lord of the Rings");

class B {
    HashMap<Integer, String> m;

    B() {
        m = new java.util.HashMap<>();

    void s(int i, String t) {
        m.put(i, t);
        System.out.println("E book added: " + t);

    void l() {
        System.out.println("E book Record:");
        for (java.util.Map.Entry<Integer, String> e : m.entrySet()) {
            System.out.println("ID: " + e.getKey() + ", Title: " + e.getValue());
Enter fullscreen mode

Exit fullscreen mode

The second, in distinction, is fairly clear – a mere skim results in an understanding of its functioning.

public class LibraryManager {
    public static void most important(String[] args) {
        Library library = new Library();
        library.addBook(1, "Harry Potter");
        library.addBook(2, "Lord of the Rings");

class Library {
    non-public Map<Integer, String> bookMap;

    Library() {
        bookMap = new HashMap<>();

    void addBook(int id, String title) {
        bookMap.put(id, title);
        System.out.println("E book added: " + title);

    void displayBookList() {
        System.out.println("E book Record:");
        for (Map.Entry<Integer, String> entry : bookMap.entrySet()) {
            System.out.println("ID: " + entry.getKey() + ", Title: " + entry.getValue());
Enter fullscreen mode

Exit fullscreen mode

Acceptable naming isn’t just vital in code. In actual fact, it’s typically much more important throughout staff discussions. In my staff, throughout discussions, we infrequently discover ourselves deeply concerned in intense arguing. Finally, we come to know that all of us agree, however now we have been utilizing completely different phrases to precise our concepts.

In my opinion, assigning clear, descriptive names, and spreading these phrases persistently throughout the staff is among the most vital duties in any mission.

Why is that this nonetheless a thorn within the facet for a lot of? The answer is easy: there is not an automatic linter/take a look at/validator that may certify your naming conventions. Every member of your staff comes with a various background, diverse experiences, and distinctive views concerning variable names. To create concord amongst these various factors takes quite a lot of time. If anybody is aware of a simple resolution for this, I might actually like to listen to it!


A couple of months in the past, my colleague Vlad, additionally the CEO, summoned me to overview a newly raised pull request (sure, our CEO is coding and it is one other ache within the ass 🙃). The stated PR is supposed to enhance how our purchasers handle their customers on our platform. We work with Spring Boot within the backend, and this mission replace included a big SQL question that was about 150 strains lengthy. This is how our dialogue went:

Nik: Vlad, nice work in your PR. Nonetheless, utilizing 150 strains of SQL is perhaps too advanced, particularly for many who see it for the primary time. In the event you’re busy with CEO work and we have to deal with it, it could possibly be powerful. How about we strive doing it in Java as a substitute?

Vlad: Certain, Nik. I foresaw some efficiency optimization, however I will go along with your judgment.

Nik: Do now we have purchasers to whom this alteration may influence considerably?

Vlad: Not but, however the scope may unfold.

Nik: Precisely. Let’s rewrite it in Java to make it simpler to learn. If we face issues that want SQL, we will change our method later.

Vlad: Sounds good.

Henceforth, the PR was rolled out to manufacturing with out a hitch, till, in fact, we started increasing it to our on-premises purchasers.

One of many on-premises purchasers had already invited a big consumer base. Nonetheless, the brand new user-management web page, launched by Vlad, took 3+ minutes to load 🥳. After all, we had then run into the N+1 drawback. I used to be like:


The N+1 drawback occurs while you first make one question to get a gaggle of most important objects (+1), and then you definately make further queries to get associated particulars for every of those most important objects (N). For N objects, you find yourself unleashing N+1 queries, akin to ordering a number of pizzas after which asking individually for every topping’s components!

Although the N+1 concern is comparatively common, it turned all too acquainted to me with ORMs (Object-relational mappings), and REST-like APIs.


Think about you will have a flowery ORM (Object-Relational Mapping) instrument. It fetches knowledge out of your database and simplifies your life till the N+1 drawback steals the present. Sarcastically, ORMs largely default to lazy loading – they seize solely the first object first, selecting the related objects solely when required. It sounds apt till you are in an N+1 state of affairs. Abruptly, your database is overworking, and also you’re left pondering: “Did I simply order a pizza, or did I begin baking the dough myself?”

Let’s check out Hibernate, an ORM instrument I typically use for examples. Think about now we have two issues: Creator and E book. These characterize authors and their books in a library. In our instance, every E book is related to an Creator utilizing a particular hyperlink known as @OneToMany(mappedBy = "creator"). This exhibits the connection between the authors and their books.

public class Creator {
    @GeneratedValue(technique = GenerationType.IDENTITY)
    non-public Lengthy id;

    non-public String title;

    @OneToMany(mappedBy = "creator")
    non-public Record<E book> books = new ArrayList<>();

public class E book {
    @GeneratedValue(technique = GenerationType.IDENTITY)
    non-public Lengthy id;

    non-public String title;

    @JoinColumn(title = "author_id")
    non-public Creator creator;
Enter fullscreen mode

Exit fullscreen mode

Suppose we intention at fetching an inventory of authors and their books by way of Hibernate. We’d take this route:

Record<Creator> authors = entityManager.createQuery("SELECT a FROM Creator a", Creator.class).getResultList();

for (Creator creator : authors) {
    // This triggers the N+1 drawback!
    Record<E book> books = creator.getBooks();

    // Do one thing with the books
Enter fullscreen mode

Exit fullscreen mode

On this instance, Hibernate begins loading authors eagerly. Nonetheless, it would not instantly fetch their corresponding books. As we pivot by way of the getBooks() methodology for every creator, Hibernate expenses forth with separate SQL queries for every creator to load their books. This encapsulates the quintessence of the N+1 drawback.

However don’t fret, fetch joins can modify our question to rapidly get each the associated books and their authors collectively:

Record<Creator> authors = entityManager.createQuery("SELECT DISTINCT a FROM Creator a LEFT JOIN FETCH a.books", Creator.class).getResultList();
Enter fullscreen mode

Exit fullscreen mode

With this, Hibernate collates each authors and their books in a single question, exiling the N+1 drawback.

Nonetheless, coping with massive datasets might not be simple, and debugging may be elusive if you do not know your method round. When dealing with efficiency points across the database, my go-to step is to totally allow SQL logging. There, I noticed quite a few queries, unraveling the N+1 drawback at hand.

REST-like APIs

Now, onto the REST-like API territory. Visualize an API that returns an inventory of entities (like superheroes), every retaining an inventory of superpowers. Making an API request to get an inventory of heroes may set off the N+1 drawback. You acquire the checklist however must make an extra request for every hero’s superpowers. It is like attending a superhero meet-and-greet, however every hero narrates their origin plot individually, and effectivity takes successful.

This is the place GraphQL shines, enabling you to specify what knowledge you require and its construction, avoiding extreme requests. Like ordering a combo meal as a substitute of separate dishes, GraphQL encapsulates your request as a single complete entity.

There are other ways to unravel the issue, not simply with GraphQL. Choices like JSON:API work too. However largely, GraphQL has grow to be the preferred alternative for this.

In abstract, N+1 may probably be the villain within the realm of programming, however gallant instruments like GraphQL may come to the rescue and restore order to this digital pandemonium. Be clever, select your heroes properly.


how to use dates in Javascript

Sure, every now and then, all of us get slapped by the confounding inconsistencies of ‘Dates.’

Regrettably, I haven’t got an interesting story to share, however I do have this checklist of date-related puzzles that left me scratching my head final yr:

  • Various Codecs: No, ‘Dates’ should not a fan of uniformity. They stroll into your system bearing completely different getups, generally even inside the similar database or API.
  • Time Zone Tango: The dance between completely different time zones for consumer and server can get fairly complicated.
  • The World Clock: Think about coping with purchasers working in varied time zones!
  • The Hour Offset Conundrum: Not all time zones proudly put on the one-hour badge.
  • Server-Time Zone Mismatch: The servers wandering in varied time zones whereas the database sticks to its personal is chaotic.
  • Leap 12 months and Leap Second: As a result of ‘Dates’ like to leap round a bit.
  • The Calendar Conversion: Changing ‘Dates’ between completely different calendars (like Gregorian, Julian, Lunar) is a formidable job.
  • Time Zone Twisters: Dealing with time zones with irregular offsets or historic adjustments is nothing in need of a rollercoaster experience.
  • Distributed Methods or Microservices: Managing time zones in these situations usually requires some hair-pulling.
  • On-Premises Deployments: Legitimate time turns into a puzzle when coping with purchasers’ on-premises deployments.

Coping with dates in programming is far more difficult than it appears. It is only one a part of the larger problem. Working with dates may be very complicated. In my expertise, issues with dates are harder than points with caching or naming. Or at the least extra irritating.


Lastly, I need to say that each one these issues are usually solvable – you possibly can clear up them in every particular person case – you possibly can title one variable correctly, you possibly can take care of scrolls on particular person pages, you possibly can design how you’re employed with dates in your system and you may make it possible for this actual controller methodology doesn’t have N+1 drawback.

Nonetheless, fixing them on the whole is simply too arduous and I do not suppose is feasible – you possibly can’t someway pressure your staff to call all of the variables, features, and courses correctly. You may’t make one easy setup and make it possible for all of the scrolls within the system are all the time an identical. You may’t add a couple of exams and make it possible for dates in your system work accurately, essentially there might be somebody who will skip your guidelines and by accident break the system.

What can we do right here? We’re making an attempt to make use of the Pareto rule and get 80% of outcomes utilizing 20% of the time – doing small easy steps to stop many of the points. Doing code evaluations, doing hacks as defined within the scrolls part (enabling scrolls in all places), doing testing for essential flows, and so on. We all know we will not catch the whole lot, so there may nonetheless be issues when it is truly deployed to manufacturing.


This can be a checklist of programming points that I discover notably irritating. What are the coding challenges that annoy you probably the most? Please share your ideas with me!


Hit a remark for those who just like the off-by-1 drawback clarification.

Add a Comment

Your email address will not be published. Required fields are marked *

Want to Contribute to us or want to have 15k+ Audience read your Article ? Or Just want to make a strong Backlink?