Senior Software Developer

New software developers are often asking themselves, and others, what is it that makes developers to be considered senior?
Some senior developers, also ask themselves if and why they are considered senior (usually when they are seeking a new workplace).
Is there a list of things that I need to do in order to become senior? I would say No, and yes. Well there is no algorithm to measure how much senior a person is. Seniority is a matter of experience. And yes, there are a few ways of gathering experience.

I laugh everytime I see the distinction of senior developers as those having 5 years of experience or more. Imagine a guy who started working on his first job on the 1st of July 2011. He should be very happy right now, because in 3 days he will be baptised "a senior", as it will be the 5th anniversary of his carreer.

I will try to summarize my thoughts here. Here we are with some pragmatic points I consider as general directions to what exactly software development experience is. And everything in this list comes with a lot of experience:

• to know and recognize software design patterns
• to know and apply what is known as best practices
• to have holistic view of the solution or system or application
• to be up to date with existing and new technology developments
• to have the ability and mood to test and measure different things while designing a solution
• to be able to define the trade of technicalities with business needs and time management

Experiment as a word contains the word experience. That's what experiencing things mean. Experience means conducting experiments, and an experience software developer is the one who has experimented a lot. And of course your experiments should be based upon experiments of other people. The programming languages you use, the libraries, the frameworks and the virtual machines are (successful or not) experiments of other people. If you are not based on others' experiments, then you would need to experiment on whether "if" works as it claims, or whether "for loop" loops exactly the number of times it should!

You get some sort of experience when you are reading a book or an article about a technology, but still, this experience is far from conducting an actual experiment.
You are actually reading the procedure and the results of an experiment that was conducted by someone else. That's not bad. It's great!

That said, the most purely experienced software developer is not the one who has read a lot. It's most probably the one who have participated in a lot of different projects.

I know people who are working on the same project for years. I can't say they are not experienced. They have achieved to master another aspect of the experience: "deep" experience is often mentioned.
This is the kind of experience that can probably be referred as "specialization". And of course, "deep" experience or specialization does not come by itself... You have to mention right after "what" this "deep experience" or "specialization" is in. I mean you must be specialized in something, right? It's quite contradictary to be specialized in something that is abstract or too general...

Last but not least: have in mind that keeping up with a project for years means that it's complex enough, at first, and above that, it keeps your interest high, it's challenging. In other words, it has to be an evolving project. Otherwise, you will be "specialized" or "deeply experienced" in such a small amount or range of stuff that could make you feel embarassed.

Rollback a specific commit and replace with the correct one - in git

For a specific task I should delete some files, move some others and update some more.
I committed something that was not completely correct (commit A). I needed to delete that commit and create a new one, to replace the old commit.
My options were:

1. to amend the commit (commit A) by making some corrections
(commit Y) <=================================== master
   |
   \
    -(commit X)-(commit A) <================ my-branch-name

2. to create a reverse commit and create a new correct commit (results in multiple commits)
(commit Y) <=================================== master
   |
   \
    -(commit X)-(commit A)-(reverse commit A)-(commit B) <== my-branch-name

3. to reset to the commit X, create a correct commit (commit B) on it, and then reset the HEAD of my-branch-name to that commit.
(commit Y) <=================================== master
   |
   |                     (commit A)
   \
    -(commit X)-(commit B) <================ my-branch-name

Option 1: amend previous commit

Option 1 would be as follows:
On top of the erroneous "commit A" I should provide all the corrective actions, stage them, and then amend the previous commit:
    git commit --amend

Option 2: create reverse commit

Option 2 has the below defects:
        * There were multiple deleted and moved files. It wouldn't be optimal to create a reverse commit and reapply my changes, since the commits should be squashed later.
        * The final changes should be included in a single commit, not multiple.

Option 3: reset to a specific commit

Option 3 is the most elegant and appropriate solution, especially when the changes are created by a script.

E.g. on the first run, the input of the script caused some changes and the commit A has been created. After that, new entries for the input of the script are coming. Then instead of finding which changes are not yet committed with commit A, it's better to reset to the previous commit, and execute again the script with the full new input. This will create a new complete set of changes that can be included in a single commit.
Execution of the script created changes A, B, D, F and G. All these changes are included in a new commit: "commit A". "Commit A" is the HEAD of my-branch-name.
New extra input to the script creates changes A, B, C, D, E, F and G. Imagine that this list could include thousands of entries. It's not easy to find the differences between the lists of changes and amend the "commit A".

To remove from the history my last erroneous commit (commit A), I need to reset the current branch to one commit backwards:
        git reset --hard HEAD~1

Perform the correct set of changes, and commit (commit B)
        git commit -m "comment for commit B"

To reset the current branch HEAD to the correct "commit B", that is not shown in git log, I can find the sha1 id of that particular commit executing:
        git reflog
       
And to reset the HEAD of my-branch-name to that commit I execute:
        git reset --hard <commit-B-sha1>

My opinion on technical debt

Definition of debt.

Speaking for a debt, we have to know that there are two participating parties: The debtor and the creditor. The debtor has an idea, and needs some assets to realize it. These assets are not immediately available to the debtor, but they are estimated to be available to him in a computed amount of time. Here is the point where the creditor enters the game. The creditor has immediately available these assets that are needed by the debtor, and he wants to sell them to him. Of course, the transaction cannot be completed once-off, so the two parties agree on an arrangement. The motivation of the creditor to start with this arrangement is the interest that will be derived. This is an investment for the creditor, and a bet for the debtor.

The debtor is now facing the challenge that he should succeed with his idea, so, he can return the value of the assets plus the interest, and of course, he should be able to make a profit for his own effort.

Metaphorically, everyone has an idea in any time of his life, and he always has to make decisions while realizing it. Right decisions are proven to be those that result to a profitable outcome. Profitable outcome of course means that the returning value of the assets and their interests are safe, being a wide variety of possible things, like ethics. Good ethics mean there is trust of the environment to the debtor, and the debtor can count on it in the future.

Software development economy.

Software development is usually driven by contracts between clients and software houses (software service providers). There is a system of managers, marketing teams and accountants etc. except from the technical team, participating to a project. And finally there are governments with tax returns. Both clients and service providers are obliged to return taxes while working for the success of their projects.

So, inevitably, in a system that every process is translated into money (salaries, contracts values, profits, taxes), decisions are driven by money also.

A client asks for a specific (the best he can do) solution to some problems, and he is making an investment, in order to make some profit. The software service provider offers the solution for a profitable price. When the contract is signed, the deadlines are the most important effects of the project for the client.

Parallelism of technical debt in software development.

Technical debt is of course a matter of work ethics. But it is not only that.

When a new contract is signed, a war starts at the premises of the software service provider. The contract may already have been evaluated, but in many cases only pre-sales department is familiar with it. Technical teams evaluate the project in order to estimate if the deadlines are feasible. I remind you that the contract is already signed, and of course it contains some deadlines, but technical teams hardly know that. Managers brainstorming team will evaluate technical estimations and they are responsible for the final agreement of the time-plan. The best manager will have the best idea: the new software solution may be a compilation of older legacy projects that have already been tested on production environments, so, there is a considerable reduction of implementation and testing efforts. Integration implementation and testing is usually a hidden cost to everyone, except from the developers. Managers’ favorite word in software houses are modules. And because they call them like this, they thing that it’s always very easy to be configurable and reusable – loosely coupled with a specific product.

Decisions are the drivers of our path through any attempt, even if they are technical decisions concerning the development of software solutions. Unfortunately, decisions in such cases are taken by the service provider’s managers because they are considered to be higher in hierarchy than senior developers or even architects. The reason is that between the roles of a manager are also some financial responsibilities.

Technical debt may be derived from technical decisions and/or financial decisions combined. Technical debt means that a project is technically inefficient because it costs too much to maintain and to evolve. There are technical and financial terms together in the same sentence (isn’t it great?).

And here comes the quality of the software. Definitely, a software solution or a software provider with a technical debt is not considered to be able to offer high quality of products/services. Wrong or biased decisions in financial and/or in technical aspects lead to low quality of products/services. And why is it called a technical debt? Because someone is called to deal with the defective product/service, working overtime, sacrificing weekends and over-negotiating to convince clients. The product/service by itself is hardly making money for the investor and his interest. The service provider is pushed to work extra for his profits. This extra work may be offered by the technical team, or by the managers’ team: technical team can work overtime for months in order to improve the quality, or the managers can be super-convincing negotiators and they can guarantee sustainability of a low quality product/service.

Conclusion.

Finally, I have to mention that hard problems need good and experienced solvers.

A system that has to be built from scratch with well written, frozen functional specifications, defining solid and clear functionality is the perfect task for junior developers. Of course we need some senior developers and an architect at least for any serious software solution delivery, but the majority of the team members should be, and can be, junior developers.

Senior developers are better and more appropriate for solving difficult problems. When the software is a mess, and the deadlines are strict, a developer should avoid a lot of pitfalls and face some challenges. Experienced developers, with strong problem solving abilities are more than suitable then. That’s why senior developers get paid better. In other words, technical debt is a decisions problem that immerse sooner or later in every software service provider. And the key to resolve this problem is to have capable and experienced members in the working team.

In a world with perfectly defined and frozen functional specifications, with frameworks and platforms that are fully compatible with each other, senior developers would be a luxury, and technical debt would be an artificial literary term.

Infrastructure for e-commerce web applications

Assets management system

In my previous job, I met a very good professional software developer who was considered to be the most experienced on the field of assets management. In the past he participated in a team developing an award winning assets management system. It was then when I realized the importance of this kind of systems. I realized that the image uploading web sites are actually assets management systems. Assets in their case are pictures.

Thinking deeper and cleaner, somebody could realize that a blogging web site is also an assets management system. A blog post is considered to be the asset in this case. It’s called a content management system because the asset is a more complex structure than monolithic binary data of images, and because there are features of presentation of assets (blog posts), filtering according to their properties and designing pages that include lists of assets.

Video management web sites are also asset management systems. In this case the assets are video files which, are assigned searchable properties, offer online editing, offer recommendation engines that lead the visitors to other videos of the same provider etc. Services vary, of course, by provider.

Thinking more widely, even an online store is an assets management system. Every product that is available for sale is an asset, and the web site is offering several features of searching and recommending assets (products) with the target of selling as much as possible.

Databases for assets persistence

Viewing everything that is served on the net as an asset, then databases can be seen as assets management systems from an application’s point of view.

Relational databases hold data tables that contain entries that describe entities. In most cases a set of joined tables describe a more complete entity. This entity may be considered an asset for an application. Object relational mapping (ORM) frameworks help developers handle multiple joins transparently, and consider a complex entity as a high level object that can be served by the application as an asset.

Architecturally simpler is the concept of the NoSQL movement. Object databases can store both structured and unstructured data, together with their properties and with the ability to change the structure of the object at any time of the application lifetime.

Provided services/functionality

1. Store an asset 
2. Retrieve an asset

User management system.

Users are entities that participate more actively in an application. They can be considered as assets to applications like social media and to applications that maintain a profile for each user. The most commonly used purposes of users are the access rights management that may be related to licensing, persistence of preferences and personalization of content.

Provided services/functionality

1. User registration 
2. Check login

Campaigns e-mail management system

Newsletters sending is a very popular way of advertisement. In a newsletter, a possible customer can be updated about the latest products and offers of a known company, without even visiting their site. This is the magic power of e-mail. Checking your email, feeds from your subscriptions arrive, without even visiting any other web-site. Of course the e-mail is linked with particular pages of the site, and the clicks on the newsletter are tracked. Customers relationship management system will be very happy to know that a customer is interested in a particular offer/product.

Another very important feature of a well designed and responsible system is the notifications engine and the most popular way of notifications is e-mail. The customer should be notified about his orders, and additionally he could set notifications on custom events provided on the web-site (e.g. notification when a product is available again, notification about changes of a product's price, notification when a new product is entered.)

Maybe the above functionality is more appropriately included in the features of the customers relationship management system, or the user management system. E.g. whether a user allows the application to send him e-mails maybe better included in the user management system. When a customer is interested in a particular product and he needs notifications on that product, then the customer relationship management system is more appropriate to include this information. The e-mail management system should probably remain agnostic of the business logic, and execute simple commands like sending a given e-mail to a given list of recipients.

Warning, I have seen some newsletters including the list of recipients in the 'To' field of the e-mail. Please include the list of recipients in the 'Bc' field of the e-mail, or send the e-mail in a loop including a single recipient at a time. Sending the newsletter in a loop using single 'To' recipients may cause a problem on your mail server with too many connections.

Provided services/functionality

1. Subscribe to the newsletter 
2. Unsubscribe from the newsletters
3. Send this content to this list of recipients

Payments system.

Of course the target of an e-Commerce application is the completion of an order and the payment from the customer. Payments are procedures that are offered by financial banking credit systems, and an e-Commerce application needs an interconnection with such a system. Payments are usually time consuming and asynchronous processes and these systems usually offer monitoring features of the progress.

Provided services/functionality

1. Submit payment with credit card for specific amount and user
2. Submit payment with bank wire-transfer for specific amount and user
3. Submit payment with online payment provider (paypal)
4. Get status of payment for an order

Shopping cart system.

Shopping cart is actually a list of selected products by a user that can be updated as he uses an e-commerce application. The cart can be only one for every user, and sometimes some applications may offer multiple carts as main or draft or temporary.

Provided services/functionality

1. Set assets management system 
2. Add product to the basket 
3. Delete product from the basket 
4. Change amount number of items for product 
5. Get the data of the basket 
6. Clear basket

Customers relationship management.

This is the system that holds the orders of the customers. It may also hold pre-orders, and calculate possible discounts. This is generally a history of transactions.

Provided services/functionality 

1. Create order 
2. Get list of orders with criteria 
3. Get discount for this shopping basket

Advertisements serving system.

Advertisements may be another additional way of profit for an e-commerce application. Suppliers may need an extra boost of promotion of their brand name or a specific product. Users may be interested for personalized advertisement messages, according to their previous purchases, the contents of their shopping cart (or carts), and of course according to their demographic data.

Provided services/functionality

1. Store an advertisement and its properties 
2. Retrieve a specific advertisement 
3. Retrieve a specific advertisement with parameterisation 
4. Retrieve an advertisement according to keywords and other criteria

A year full of passion

I just turned an exciting year on my current job at www.xe.gr. I feel that much happened during this year, and now it's time for an account of things done, and scheduling tasks to be done in the future.

During this year:
1. I contributed to an e-commerce application and its shopping cart.
2. I got introduced to the Restless services, and implemented a restless API.
3. I found out that there are JSP alternatives, that are better for front-end developers.
4. I discovered the power of dynamic languages. Perl, Python and Scala are now in my immediate interests.
5. I realised that Tomcat servlet container can do the job as an "application server". JBoss, Websphere and Weblogic are great application servers for those who don't care about the overhead (or configuration) of preinstalled frameworks.
6. I dropped my absolute belief to relational databases as Oracle and MySQL, as I discovered NoSQL databases as MongoDB and Cassandra.
7. Now I am aware of over a hundred open source projects that can be usefull and I must use during my career.
8. I studied many lines of bad written legacy code, and I supported it.
9. I was introduced to the agile development process, and especially to Extreme Programming.
10. I used 2 major bug tracking systems professionally: Bugzilla and JIRA.
11. I created an account to a social network for professionals: linkedin.com
12. I created my account on twitter and twitted about 50 times.
13. I dropped an eye out of the box and I saw Javascript can be a server side programming language.
14. I decided to regulary attend the meetings of 2 user groups: jhug (Java Hellenic User Group) and greecejs (greek javascript user group).
15. I first used Maven as the build tool of my projects.
16. I extensivelly used subversion for versioning.
17. I created my account at github, started 2 new open source projects and started learning git for versioning.
18. I recently acquired an android smartphone, so, I started using mobile internet and I read more using the kindle application.
19. Now I can see much more potential in the smart mobile devices, and as a result I care more about mobile software development.
20. I purchased about 15 ebooks and 5 printed books about software development.

Phew! Pretty awsome and fascinating year!
And there is more...
I met great people with great personalities, who communicated their invaluable experiences and their interestingly different point of view.
I made some friends, and I spent great time lunching and drinking beers.

At the personal level, I admit that the current and the next year will be the greatest years of my life because in a few months I will take the greatest responsibility of my life: being a father.