How to get your first professional experience while working in another industry?
It depends on your skill, education, and personal financial obligations. If you have a relevant 4 year degree, moderate skill, and can afford it, you should just switch industries. Most companies have a very flexible definition of relevant when it come to 4 year degrees so almost any will do. On the other hand, most companies require 3 years of relevant experience for each year lacking in education. If this is the case, I would recommend finding a part-time "fresher" position and try to juggling the two jobs.
Thank you for answer. I have to find part-time job but i've never seen job ofert like that.
Well, in the US and India the description "fresher" will be used for coding jobs with little to no experience needed. Like "Java fresher position available". I am not sure what the Polish equivalent would be. LinkedIn and Indeed.com both pull up fresher positions.