Education and self-teaching would not be enough to build up the reliable set of skill. This is the list of places where I learnt the craft on the job.
Where I work(ed)
Working Student at Nokia Siemens Networks
During my work as a Working Student I was a part of a team responsible for development and maintenance of one of most important products of our department.
The tool was used by company's experts to perform the dimensioning as well as network optimizations. Additionally, I was delegated to create and maintain an updater client (and server), which were intended to be shipped with said product.
My work was mainly concerned with Java development, and required of me proper implementation of features according to the specification, creation and maintenance of unit and functional tests and, occasionally, maintenance of our Jenkins CI server and Gradle build script.
It gave me a huge opportunity to learn from experienced professionals proficient with good programming practices and valid Agile workflow, which allowed me to boost and polish my skills.