Why your software get bugs year after year

Human, machine or money are all involved.

*Software here mentions to every kind of PC applications, web applications, mobile applications

The very first year of my software developer career is to be a bug killer. The year that I joined, I can feel that there is no thing new added to the product, everyone seemed to have to spend a year, actually more, to fix bugs that created just from prior 2 years of coding. It sounds expensive, right ! The cost for fixing bugs not only employees wage but also the trust from customers, and sometime to be a loser to your competitors. At least that year teaches me on how a thing can be done wrong and I do believe that, knowing how to do it WRONG is even more important than knowing how to do it RIGHT. Every mistakes are worthy to learn, even it’s yours or not.

How is human involved ?

Testers usually blame developers for bugs. Actually it’s true, but remember that they are the source of other non-bug things. People make mistakes all the time, unconsciously, and so do developers and testers too. Seniors will make less bugs than Juniors, not because Senior are smarter, it is because Seniors already made all of that mistakes in the past. Smartness only helps to figure out and solve problem faster, it does not help to avoid problems, or mistakes. The job of testers is to help to reveal developer’s mistakes, to ensure the product’s quality, so avoid carping and blaming developers for bugs.

The easiest-to-fix bugs are Programming Errors. Yes, this is all about developers. Programming Errors includes :

  • Syntax error : Each programming language has its own coding convention. Newbie in coding usually make those mistakes because they are still not have full understanding about predefined conventions. Sometime they don’t aware that style of coding even exists.
  • Semantic error: When the coder got familiar with syntaxes, they literally can tell the computer to do things they desire in which order of steps. But sometime, some steps conflict with others such as altering a value that is still not available, or steps are executed in a wrong order that leads to producing a wrong result. Null pointer exception maybe the most famous error that developers and testers ever heard during their jobs. It is when the computer are asked to read a value that doesn’t exist in its memory. The more experience developer, the easiest way they can avoid those errors.
  • Logical error: Even multiple years Senior developers still make this mistake. It is when a developer has to turn his understanding about a requirement into lines of code. And as a human and depends on how efficient the communication method is, he may mis-understand the logic then produce mis-behavior code. When he has correct understanding about requirements but still produces wrong things, it is because of later reasons.
The main different between Junior and Senior developer

The next level of complexity bugs are from Communication Error. This time, it is about everyone: product owners, business analyst, developers, testers, managers, and the cat of developers.

There are always communication gap between any couple of people. If a team lacks of the co-operation or is weak at co-operation, its number of members does not reduce development time, it increases, because the more inefficient communication is, the more problems come. And again, please don’t mis-percept between communication versus talky or chat, or gossips. Communication Error here is about the mis-distributing information between people. It is the lack of Reporting systems between stakeholders. Lack of information leads to wrong understanding and even conflicting, not only in human aspects, but also in product design and development process.

  • Reporting between Developer and Developer: This is the most popular problem in a development team. A typical phenomenon is a developer usually re-invent a thing that already exists, not because to improve or to overcome some limitations, but because he doesn’t aware of its existence. And as we know, any inventions must go through a lot of mistakes, and re-invent is to go to face to those mistakes again. Mistake is bug!
    In scope of developers, the lack of reporting on what is done, what is being done, what will be done creates blind spots in making decision on how to write code. Writing new things is time consuming and much error prone. Using existing ones but without document or guidance is error prone too. Well organized tech meeting is a good practice to distribute information. A serious Technical document and good distributing methods also can ensure developers knowledge synchronized and then less error prone.

  • Reporting between Business analyst and Developer : Lacking of reporting on what is doing good, what is doing poorly and why this, not that also create smoke lines in developers mind. Everyone has their own past and the past creates assumptions. Sometime you find out a developer build things in his manner way that he believes is right but it does not fit to your current business logic. Don’t assume people understand things in your manner way. So, to make developer understand the situation, please also let them know what customers do, how customers do that and why customers do that way.
  • Reporting between Product Owner and Business Analyst : This is usually merely verbal communication. This communication step turns an idea to detail actions that developer later will engage with. And idea is something mutable. The change in idea creates the change in requirements. And changes in requirement, if not are clarified carefully, it can cause conflict with old requirements or mismatch to them. And this case, even developers do exactly as requirements, the software still gets bugs. It is business logic bug. To reduce this case, business analyst should have a method to oversee the affection between business rules, so that can report early to the “idea generator” potential problems, then in turn, with Product Owner to clarify the final and safe actions needed. The Product Owner also should give a clear vision and strategy so that everyone can have a particular destination in mind and in turn, it helps everyone adjusts their own actions to fit to the strategy. Do you believe that the idea itself can bug?
  • Reporting between Employee and Manager: Managers are familiar with reporting. They use information reported from others stakeholders to create detail action plans. For some reasons, budget for example, or mis-estimating required effort, the deadline for an action is sometime too tight. It create a time pressure on developer and tester. With limited time, everyone will choose the fastest way. Developer will choose hard-code solution, testers will miss some test cases, and eventually, bugs will emerge. Hard-code is to cure an illness by cover up symptoms without applying time-consuming proven treatments.

  • Reporting between Testers : The job of tester is to manage test cases and go through them, often. With some coding knowledge, testers can write automation tests that can automatically run after every changes in requirement, big or small. This is the most efficient way for testers. In some case, testers are non-tech, developers usually take care this part too. Without automation tests, testers will have to manually test case by case after each change in requirement. Testers should not assume that developers will take care all affections of the change to other functions. Sometime developers even do not aware about that. Fixing bugs can create bugs too. So, if you are tired with manual tests, create automation tests.
  • The cat of employees : This is a metaphor for employee’s mental health. It does affect to employee’s alertness and is a cause to create mistakes. A broken heart is more likely to destroy the system more than a normal one, right. So, make sure your team is heathy.
How is machine involved ?

Beside mistakes obviously made by human, there are some objective conditions can make your software run some undesired behaviors that customers can report as bugs. Actually someone can blame developers about their inability to anticipate those conditions, please remember that it is also because tester’s inability to anticipate those conditions, and it does not in the requirement written by BAs or Product Owner too.

Experienced developers can aware about those situations and can give early solutions. But everything takes time. Especially, solving those kinds of bug requires more effort than above ones. Testers should aware about those situations and learn more advanced testing techniques so that can help to reveal those problems early before it happens to end users.

  • Incompatibility: Your customer’s machine can have some limitations to be sufficient to run your software. It can be a low memory computer (RAM, Hard disk) , old (weak) processor or out-update Operating System. Every software will need a minimum available memory and pre-existing components for initializing and further executions. When the computer run out of resources, anything can run improperly. Every software should be shipped with a system requirement note, it can act as a disclaimer term for your team.
  • Memory Consumption : With the same problem, each developer can have different solutions and each solution has a different speed and memory consumption. Memory is a limited resource. Much or less, this depends on developer’s skill. But with nowadays computer power, a few Gigabytes memory is usual so it makes most of developers in most of situations does not so care about memory consumption anymore, until it crashes.
    Running out of memory not only is caused by your own software. A computer can run many softwares as the same time so it is not always because of you. It is the best if the software can notify to users about its memory situation so the user can understand what is going wrong.
    In web servers context, each request is allocated a maximum memory amount. This practice is to ensure the server can handle hundreds to thousands requests per seconds. The code written by developers may not consume so much memory, but it may exceed this threshold. Many other components behind the scene like databases, proxies, other third party services are all vulnerable by this problem. So to developers, never assume everything does well, always prepare for the failure because bad things do happen.
  • Unstable Network: Offline-only software has nothing to worry about this. This is more important for software that has client-server model. Most of application nowadays is client-server model. The connection quality between client and server is extreme important, especially with application requires realtime responses like stock market, online gaming or streaming services. The technology behind those applications already has some tactics to recover or endure under unstable network or low bandwidth connection, but they are “try best” only, don’t expect it has magic. The ability to work under low bandwidth or unstable connection, to some application like video streaming, is the key competition factor. Testers should aware about this and should have serious test scenarios.
    To optimize solutions to make sure the software can work under this situation, developers must have deep knowledge about computing and networking. Fix those kind of bug is extreme hard. Don’t expect the solution is always available, current Civilization still have some limitations.

  • Offline Accidents: Electricity off, for some reasons. The suddenly shutdown can cause some functions in a program fail partially. It can cause some problem in the next start such as mismatch data or corrupt data. Some softwares handling sensitive data like in banking industry for example, usually have some recover strategies, digital and non-digital to ensure the business from damages.
How is money involved?

Budget of a project affects to the plan in time pressure and the priority of works. Most of time, developer will focus first on writing code to fit with business logic and let aside potential problem about machine. It makes sense because we should avoid the Pre-mature Optimizing: how sure that potential problem will happen? This ignorance from priority reason produces something called Technical Debt, and every debts need to be paid, soon or late, with or without interest.

Budget determines the quality of team members. It obviously the more experience employees, the more benefit they want. Experience means they are aware about mistakes and they do have a way to avoid them. And when they know how to avoid mistakes, they know how to do it right.

Budget affects employee’s motivation. Motivation makes them do their best to make the best software they can. Sometime your software does not make money enough to ensure that kind of employee’s motivation or minimum member quality, remember my question: “Do you believe that the idea itself can bug“? If your software does not make enough money YET, why not share your vision with everyone and let them be one of it. Excellent people who willing work for joy and opportunity still exists, trust me !!.


Above is some senses from my debugging era. Hope it can help to point out some mysteries from developer world and help teams has more appropriate actions to deal with bugs. Feel free to comment for anything you interested in or not agree. Thanks for your time.